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2023 Volume 34 Issue 1
2023, 34(1): 106898
doi: 10.1016/j.cclet.2021.10.078
Abstract:
2D MBenes have been theoretically predicted to possess unique electronic structures and physicochemical properties, and thus shown great promise in various applications. However, the synthesis of individual single-layer MBene remains a grand challenge due to its orthorhombic structure of MAB phases. Recently, scientists from Linköping University have fabricated 2D monolayer Mo4/3B2-xTz with ordered metal vacancies. Their results demonstrated the feasibility of top-down approach by chemical exfoliation of laminated compounds and provided the principle for further preparation of a wealth of MBenes.
2D MBenes have been theoretically predicted to possess unique electronic structures and physicochemical properties, and thus shown great promise in various applications. However, the synthesis of individual single-layer MBene remains a grand challenge due to its orthorhombic structure of MAB phases. Recently, scientists from Linköping University have fabricated 2D monolayer Mo4/3B2-xTz with ordered metal vacancies. Their results demonstrated the feasibility of top-down approach by chemical exfoliation of laminated compounds and provided the principle for further preparation of a wealth of MBenes.
2023, 34(1): 106917
doi: 10.1016/j.cclet.2021.11.005
Abstract:
Chemical fixation of CO2 into C1 source, as a general approach, can effectively alleviate the emission of greenhouse gasses. Whereas, the challenge posed by the need for efficient catalysts with high catalytic active sites still exists. In this work, we reported a series of new hexavanadate clusters, [(C6H6ON)2(C2H8N2)2(CH3O)6V6IVO8] (V6–1), [(C6H6ON)2(C3H10N2)2(CH3O)6V6IVO8] (V6–2), [(C6H6ON)2(C6H14N2)2(CH3O)6V6IVO8] (V6–3) and [(C6H6ON)2(C4H11N2O)2(CH3O)4V6IVO8] (V6–4), assembled by 2-aminophenol and four different kinds of Lewis bases (LB), ethanediamine (en), 1,2-diaminopropane, 1,2-cyclohexanediamine and N-(2-hydroxyethyl)ethylenediamine (ben) together. Among them, the basic unit {V6} cluster featured Z-shaped configuration represents a brand-new example of hexanuclear vanadium clusters. Remarkably, the catalytic tests demonstrated that V6–1 as catalyst displays high catalytic activity in the cycloaddition for the CO2 fixation into cyclic carbonates by virtue of open V sites. As expected, for oxidative desulfurization of sulfides, V6–1 also exhibits satisfied catalytic effectiveness. Furthermore, the recycling test confirmed that catalyst V6–1 may be a bifunctional heterogeneous catalyst with great promise for both CO2 cycloaddition and oxidative desulfurization reactions.
Chemical fixation of CO2 into C1 source, as a general approach, can effectively alleviate the emission of greenhouse gasses. Whereas, the challenge posed by the need for efficient catalysts with high catalytic active sites still exists. In this work, we reported a series of new hexavanadate clusters, [(C6H6ON)2(C2H8N2)2(CH3O)6V6IVO8] (V6–1), [(C6H6ON)2(C3H10N2)2(CH3O)6V6IVO8] (V6–2), [(C6H6ON)2(C6H14N2)2(CH3O)6V6IVO8] (V6–3) and [(C6H6ON)2(C4H11N2O)2(CH3O)4V6IVO8] (V6–4), assembled by 2-aminophenol and four different kinds of Lewis bases (LB), ethanediamine (en), 1,2-diaminopropane, 1,2-cyclohexanediamine and N-(2-hydroxyethyl)ethylenediamine (ben) together. Among them, the basic unit {V6} cluster featured Z-shaped configuration represents a brand-new example of hexanuclear vanadium clusters. Remarkably, the catalytic tests demonstrated that V6–1 as catalyst displays high catalytic activity in the cycloaddition for the CO2 fixation into cyclic carbonates by virtue of open V sites. As expected, for oxidative desulfurization of sulfides, V6–1 also exhibits satisfied catalytic effectiveness. Furthermore, the recycling test confirmed that catalyst V6–1 may be a bifunctional heterogeneous catalyst with great promise for both CO2 cycloaddition and oxidative desulfurization reactions.
2023, 34(1): 107085
doi: 10.1016/j.cclet.2021.12.077
Abstract:
Supramolecular chemistry has received considerable attention in host-guest recognition. The structure-response relationship of host-guest recognition system is a meaningful issue. Herein, a series of tripodal nitrogen mustard derivatives (TMs) have been developed in this paper. By rationally design the intramolecular alkyl chain lengths of host, the host-guest binding model have been successfully tuned, which underwent a transformation from π-π to multiple hydrogen bonds. This process enhances the host-guest binding force and recognition efficiency.
Supramolecular chemistry has received considerable attention in host-guest recognition. The structure-response relationship of host-guest recognition system is a meaningful issue. Herein, a series of tripodal nitrogen mustard derivatives (TMs) have been developed in this paper. By rationally design the intramolecular alkyl chain lengths of host, the host-guest binding model have been successfully tuned, which underwent a transformation from π-π to multiple hydrogen bonds. This process enhances the host-guest binding force and recognition efficiency.
2023, 34(1): 107125
doi: 10.1016/j.cclet.2022.01.018
Abstract:
Fabricating an efficient charge transfer pathway at the compact interface between two kinds of semiconductors is an important strategy for designing hydrogen production heterojunction photocatalysts. In this work, we prepared a compact, stable and oxygen vacancy-rich photocatalyst (SnO2/TiO2 heterostructure) via a simple and reasonable in-situ synthesis method. Briefly, SnCl2–2H2O is hydrolyzed on the TiO2 precursor. After the pyrolysis process, SnO2 nanoparticles (5 nm) were dispersed on the surface of ultrathin TiO2 nanosheets uniformly. Herein, the heterojunction system can offer abundant oxygen vacancies, which can act as active sites for catalytic reactions. Meanwhile, the interfacial contact of SnO2/TiO2 grading semiconductor oxide is uniform and tight, which can promote the separation and migration of photogenerated carriers. As shown in the experimental results, the hydrogen production rate of SnO2/TiO2 is 16.7 mmol h−1 g−1 (4.4 times higher than that of TiO2), which is owing to its good dynamical properties. This work demonstrates an efficient strategy of tight combining SnO2/TiO2 with abundant oxygen vacancies to improve catalytic efficiency.
Fabricating an efficient charge transfer pathway at the compact interface between two kinds of semiconductors is an important strategy for designing hydrogen production heterojunction photocatalysts. In this work, we prepared a compact, stable and oxygen vacancy-rich photocatalyst (SnO2/TiO2 heterostructure) via a simple and reasonable in-situ synthesis method. Briefly, SnCl2–2H2O is hydrolyzed on the TiO2 precursor. After the pyrolysis process, SnO2 nanoparticles (5 nm) were dispersed on the surface of ultrathin TiO2 nanosheets uniformly. Herein, the heterojunction system can offer abundant oxygen vacancies, which can act as active sites for catalytic reactions. Meanwhile, the interfacial contact of SnO2/TiO2 grading semiconductor oxide is uniform and tight, which can promote the separation and migration of photogenerated carriers. As shown in the experimental results, the hydrogen production rate of SnO2/TiO2 is 16.7 mmol h−1 g−1 (4.4 times higher than that of TiO2), which is owing to its good dynamical properties. This work demonstrates an efficient strategy of tight combining SnO2/TiO2 with abundant oxygen vacancies to improve catalytic efficiency.
2023, 34(1): 107128
doi: 10.1016/j.cclet.2022.01.021
Abstract:
Traditional methods of preparing metal-organic frameworks (MOFs) compounds have the disadvantages such as poor dispersion, inefficient and discontinuous process. In this work, microchannel reactor is used to prepare MOFs-derived zeolite-imidazole material via flash nanoprecipitation to form ZIF-67 + PEI(FNP), which reduces the MOF synthesis time down to millisecond time interval while keeping the synthesized ZIF-67 + PEI(FNP) highly dispersed. The Co@N–C(FNP)catalyst obtained by flash nanoprecipitation and carbonization has a higher Co content and thus more active sites for oxygen reduction reaction than the Co@N–C(DM) catalyst prepared by direct mixing method. Electrochemical tests show that the Co@N–C(FNP) catalyst prepared by this method has excellent oxygen reduction performance, good methanol resistance and high stability. The onset potential and half-wave potential of Co@N–C(FNP) are 0.92 VRHE and 0.83 VRHE, respectively, which are higher than that of Co@N–C(DM) (Eonset = 0.90 VRHE and E1/2 = 0.83 VRHE). Moreover, the Zn-air battery assembled with Co@N–C(FNP) as the cathode catalyst has high open circuit voltage, high power density and large specific capacity. The performance of these batteries has been comparable to that of Pt/C assembled batteries. Density functional theory (DFT) calculations confirm that the Co (220) crystal plane present in Co@N–C(FNP) have stronger adsorption energy than that of Co (111) crystal plane in Co@N–C(DM), leading to better electrocatalytic performance of the former.
Traditional methods of preparing metal-organic frameworks (MOFs) compounds have the disadvantages such as poor dispersion, inefficient and discontinuous process. In this work, microchannel reactor is used to prepare MOFs-derived zeolite-imidazole material via flash nanoprecipitation to form ZIF-67 + PEI(FNP), which reduces the MOF synthesis time down to millisecond time interval while keeping the synthesized ZIF-67 + PEI(FNP) highly dispersed. The Co@N–C(FNP)catalyst obtained by flash nanoprecipitation and carbonization has a higher Co content and thus more active sites for oxygen reduction reaction than the Co@N–C(DM) catalyst prepared by direct mixing method. Electrochemical tests show that the Co@N–C(FNP) catalyst prepared by this method has excellent oxygen reduction performance, good methanol resistance and high stability. The onset potential and half-wave potential of Co@N–C(FNP) are 0.92 VRHE and 0.83 VRHE, respectively, which are higher than that of Co@N–C(DM) (Eonset = 0.90 VRHE and E1/2 = 0.83 VRHE). Moreover, the Zn-air battery assembled with Co@N–C(FNP) as the cathode catalyst has high open circuit voltage, high power density and large specific capacity. The performance of these batteries has been comparable to that of Pt/C assembled batteries. Density functional theory (DFT) calculations confirm that the Co (220) crystal plane present in Co@N–C(FNP) have stronger adsorption energy than that of Co (111) crystal plane in Co@N–C(DM), leading to better electrocatalytic performance of the former.
2023, 34(1): 107134
doi: 10.1016/j.cclet.2022.01.027
Abstract:
Efficient CO2 reduction reaction (CO2RR) is one of the important topics in energy and environment field, but improving the electrochemical selectivity of specific product is a great challenge. Herein, we reported a unprecedented two-dimensional (2D) metal−organic framework with CuO4 unit (denoted as Cu-HHTT, HHTT = 9, 10-dihydro-9, 10-[1,2]benzenoanthracene-2, 3, 6, 7, 14, 15-hexaol) as the electrocatalyst for CO2RR. Cu-HHTT exhibits high performance for CO2RR to produce CO, namely Faradaic efficiency of 96.6% toward CO with a current density of 18 mA/cm2 at the potential of −0.6 V vs. RHE. Density function theory reveals that the desorption of CO species exhibits a lower energy barrier than that of hydrogenation of *CO intermediate, resulting in CO as the main product instead of alcohols or hydrocarbons.
Efficient CO2 reduction reaction (CO2RR) is one of the important topics in energy and environment field, but improving the electrochemical selectivity of specific product is a great challenge. Herein, we reported a unprecedented two-dimensional (2D) metal−organic framework with CuO4 unit (denoted as Cu-HHTT, HHTT = 9, 10-dihydro-9, 10-[1,2]benzenoanthracene-2, 3, 6, 7, 14, 15-hexaol) as the electrocatalyst for CO2RR. Cu-HHTT exhibits high performance for CO2RR to produce CO, namely Faradaic efficiency of 96.6% toward CO with a current density of 18 mA/cm2 at the potential of −0.6 V vs. RHE. Density function theory reveals that the desorption of CO species exhibits a lower energy barrier than that of hydrogenation of *CO intermediate, resulting in CO as the main product instead of alcohols or hydrocarbons.
2023, 34(1): 107137
doi: 10.1016/j.cclet.2022.01.030
Abstract:
Nickel cobalt bimetallic heterogeneous sulfides are attractive battery-type materials for electrochemical energy storage. However, the precise synthesis of electrode materials that integrate highly efficient ions/electrons diffusion with abundant charge transfer channels has always been challenging. Herein, an effective and concise controllable hydrothermal approach is reported for tuning the crystalline and integrated structures of MOF-derived bimetallic sulfides to accelerate the charge transfer kinetics, and thus enabling rich Faradaic redox reaction. The as-obtained low-crystalline heterogeneous NiCo2S4/Co3S4 nanocages exhibit a high specific capacity (1023 C/g at 1 A/g), remarkable rate performance (560 C/g at 10 A/g), and outstanding cycling stability (89.6% retention after 5000 cycles). Furthermore, hybrid supercapacitors fabricated with NiCo2S4/Co3S4 and nitrogen-doped reduced graphene oxide display an outstanding energy density of 40.8 Wh/kg at a power density of 806.3 W/kg, with an excellent capacity retention of 88.3% after 10000 charge-discharge cycles.
Nickel cobalt bimetallic heterogeneous sulfides are attractive battery-type materials for electrochemical energy storage. However, the precise synthesis of electrode materials that integrate highly efficient ions/electrons diffusion with abundant charge transfer channels has always been challenging. Herein, an effective and concise controllable hydrothermal approach is reported for tuning the crystalline and integrated structures of MOF-derived bimetallic sulfides to accelerate the charge transfer kinetics, and thus enabling rich Faradaic redox reaction. The as-obtained low-crystalline heterogeneous NiCo2S4/Co3S4 nanocages exhibit a high specific capacity (1023 C/g at 1 A/g), remarkable rate performance (560 C/g at 10 A/g), and outstanding cycling stability (89.6% retention after 5000 cycles). Furthermore, hybrid supercapacitors fabricated with NiCo2S4/Co3S4 and nitrogen-doped reduced graphene oxide display an outstanding energy density of 40.8 Wh/kg at a power density of 806.3 W/kg, with an excellent capacity retention of 88.3% after 10000 charge-discharge cycles.
2023, 34(1): 107144
doi: 10.1016/j.cclet.2022.01.037
Abstract:
Thanks to tunable physical and chemical properties, two-dimensional (2D) materials have received intensive interest, endowing their excellent electrocatalytic performances for applications in energy conversion. However, their catalytic activities are largely determined by poor adsorption energy and limited active edge sites. Herein, a one-step electrochemical exfoliation strategy was developed to fabricate 2D Ni-doped MoS2 nanosheets (Ni-EX-MoS2) with a lateral size of ~500 nm and thickness of ~3.5 nm. Profiting from high electrical conductivity and abundant exposing active sites, Ni-EX-MoS2 catalyst displayed an admirable performance for electrochemical hydrogen evolution reaction (HER) with a low overpotential of 145 mV at 10 mA/cm2 as well as a small Tafel slope of 89 mV/dec in alkaline media, which are superior to those of the most reported MoS2-based electrocatalysts. The formed Ni species with tuning electronic structure played a crucial role as primary active center of Ni-EX-MoS2, as well as the forming stable 1T/2H phase MoS2 interface demonstrated a synergistic effect on electrocatalytic HER performance. Further, Ni-EX-MoS2 was employed as a cathode electrode for alkaline Zn-H2O battery, which displayed a high power density of 3.3 mW/cm2 with excellent stability. This work will provide a simple and effective guideline for design of electrochemically exfoliated transition metal-doped MoS2 nanosheets to inspire their practical applications in energy catalytic and storage.
Thanks to tunable physical and chemical properties, two-dimensional (2D) materials have received intensive interest, endowing their excellent electrocatalytic performances for applications in energy conversion. However, their catalytic activities are largely determined by poor adsorption energy and limited active edge sites. Herein, a one-step electrochemical exfoliation strategy was developed to fabricate 2D Ni-doped MoS2 nanosheets (Ni-EX-MoS2) with a lateral size of ~500 nm and thickness of ~3.5 nm. Profiting from high electrical conductivity and abundant exposing active sites, Ni-EX-MoS2 catalyst displayed an admirable performance for electrochemical hydrogen evolution reaction (HER) with a low overpotential of 145 mV at 10 mA/cm2 as well as a small Tafel slope of 89 mV/dec in alkaline media, which are superior to those of the most reported MoS2-based electrocatalysts. The formed Ni species with tuning electronic structure played a crucial role as primary active center of Ni-EX-MoS2, as well as the forming stable 1T/2H phase MoS2 interface demonstrated a synergistic effect on electrocatalytic HER performance. Further, Ni-EX-MoS2 was employed as a cathode electrode for alkaline Zn-H2O battery, which displayed a high power density of 3.3 mW/cm2 with excellent stability. This work will provide a simple and effective guideline for design of electrochemically exfoliated transition metal-doped MoS2 nanosheets to inspire their practical applications in energy catalytic and storage.
2023, 34(1): 107146
doi: 10.1016/j.cclet.2022.01.039
Abstract:
Bimetallic catalysts usually exhibit better performance than monometallic catalysts due to synergistic effect. However, there is a lack of exploring the synergistic effect on catalytic performance caused by the introduction of inactive metal ion. In this work, we design a molecular model system that can precisely regulate the metal site number and catalytic property. When these molecular metal compounds are used as homogeneous catalysts for photocatalytic CO2 reduction, the dinuclear heterometallic CuNi-L2 shows the highest CO2-to-CO conversion, which is 2.1 and 3.0 times higher than that of dinuclear homometallic Ni2-L2 and mononuclear Ni-L1. Density functional theory calculations demonstrate that, in CuNi-L2, the introduction of inactive CuII is easier to promote the photo-generated electrons transferring to the coupled active NiII site to achieve the highest activity. In addition, this work also provides insights to design and construct more efficient bimetallic catalysts in future.
Bimetallic catalysts usually exhibit better performance than monometallic catalysts due to synergistic effect. However, there is a lack of exploring the synergistic effect on catalytic performance caused by the introduction of inactive metal ion. In this work, we design a molecular model system that can precisely regulate the metal site number and catalytic property. When these molecular metal compounds are used as homogeneous catalysts for photocatalytic CO2 reduction, the dinuclear heterometallic CuNi-L2 shows the highest CO2-to-CO conversion, which is 2.1 and 3.0 times higher than that of dinuclear homometallic Ni2-L2 and mononuclear Ni-L1. Density functional theory calculations demonstrate that, in CuNi-L2, the introduction of inactive CuII is easier to promote the photo-generated electrons transferring to the coupled active NiII site to achieve the highest activity. In addition, this work also provides insights to design and construct more efficient bimetallic catalysts in future.
2023, 34(1): 107152
doi: 10.1016/j.cclet.2022.01.045
Abstract:
Application of Li-oxygen (Li-O2) battery is in urgent need of bifunctional ORR/OER electrocatalyst. A surface-functionalization CoP/Ti3C2Tx composite was fabricated theoretically, with the optimized electronic structure and more active electron, which is beneficial to the electrochemical reaction. The accordion shaped Ti3C2Tx is featured with large specific surface area and outstanding electronic conductivity, which is beneficial for the adequate exposure of active sites and the deposition of Li2O2. Transition metal phosphides provide more electrocatalytic active sites and present good electrocatalytic effect. The CoP/Ti3C2Tx composite served as the electrocatalyst of Li-O2 battery reaches a high specific discharge capacity of 17, 413 mAh/g at 100 mA/g and the lower overpotential of 1.25 V, superior to those of the CoP and Ti3C2Tx individually. The composite of transition metal phosphides and MXene are applied in Li-O2 battery, not only demonstrating higher cycling stability of the prepared CoP/Ti3C2Tx composite, but pointing out the direction for their electrochemical performance improvement.
Application of Li-oxygen (Li-O2) battery is in urgent need of bifunctional ORR/OER electrocatalyst. A surface-functionalization CoP/Ti3C2Tx composite was fabricated theoretically, with the optimized electronic structure and more active electron, which is beneficial to the electrochemical reaction. The accordion shaped Ti3C2Tx is featured with large specific surface area and outstanding electronic conductivity, which is beneficial for the adequate exposure of active sites and the deposition of Li2O2. Transition metal phosphides provide more electrocatalytic active sites and present good electrocatalytic effect. The CoP/Ti3C2Tx composite served as the electrocatalyst of Li-O2 battery reaches a high specific discharge capacity of 17, 413 mAh/g at 100 mA/g and the lower overpotential of 1.25 V, superior to those of the CoP and Ti3C2Tx individually. The composite of transition metal phosphides and MXene are applied in Li-O2 battery, not only demonstrating higher cycling stability of the prepared CoP/Ti3C2Tx composite, but pointing out the direction for their electrochemical performance improvement.
2023, 34(1): 107180
doi: 10.1016/j.cclet.2022.01.073
Abstract:
Heavy metals usually exist stably as the species of organic complexes in high-salinity wastewater. Therefore, their effective removal is challenging, especially when the initial pH is neutral. Herein, a novel nitrogen doped biomass-based composite (N-CMCS) was synthesized to remove the complexed heavy metal of Cr(Ⅲ)-carboxyl. The maximum adsorption capacity of Cr(Ⅲ)-Citrate (Cr-Cit) by N-CMCS under neutral pH (7.0) and high-salinity (200 mmol/L NaCl) condition was up to 2.50 mmol/g. And the removal performance remained stable after 6 times of regeneration. Combined with species and characterizations analysis, electrostatic attraction and hydrogen bonding were the main mechanisms for N-CMCS to remove Cr(Ⅲ)-carboxyl complexes. Dynamic adsorption indicated N-CMCS column could treat about 1300 BV simulated wastewater and 350 BV actual wastewater with the concentration of effluent lower than 1.0 mg/L. Furthermore, N-CMCS could remove a variety of complexed heavy metal ions under neutral pH, indicating the great potential in practical application.
Heavy metals usually exist stably as the species of organic complexes in high-salinity wastewater. Therefore, their effective removal is challenging, especially when the initial pH is neutral. Herein, a novel nitrogen doped biomass-based composite (N-CMCS) was synthesized to remove the complexed heavy metal of Cr(Ⅲ)-carboxyl. The maximum adsorption capacity of Cr(Ⅲ)-Citrate (Cr-Cit) by N-CMCS under neutral pH (7.0) and high-salinity (200 mmol/L NaCl) condition was up to 2.50 mmol/g. And the removal performance remained stable after 6 times of regeneration. Combined with species and characterizations analysis, electrostatic attraction and hydrogen bonding were the main mechanisms for N-CMCS to remove Cr(Ⅲ)-carboxyl complexes. Dynamic adsorption indicated N-CMCS column could treat about 1300 BV simulated wastewater and 350 BV actual wastewater with the concentration of effluent lower than 1.0 mg/L. Furthermore, N-CMCS could remove a variety of complexed heavy metal ions under neutral pH, indicating the great potential in practical application.
2023, 34(1): 107181
doi: 10.1016/j.cclet.2022.01.074
Abstract:
6-Thioguanine (6TG) is a widely used chemotherapeutic agent for the treatment of a variety of human diseases including acute lymphoblastic leukemia. After entry into cells, 6TG is metabolically converted into 6-thioguanosine (SG) nucleotide that can be incorporated into the genome during DNA replication. SG in genomic DNA could induce cell death by triggering the post-replicative mismatch repair (MMR) pathway. Meanwhile, incorporation of 6TG into the CpG sites could perturb the global DNA methylation and gene regulation. However, the effect of 6TG on RNA modifications is still unknown. Adenosine-to-inosine (A-to-I) editing in RNA is one of the most common post-transcriptional modifications in mammals and there is growing evidence showing the significant alteration of A-to-I RNA editing in tumor tissues compared to normal tissues. In the current study, we examined the incorporation of 6TG into RNA and investigated its effect on A-to-I editing of bladder cancer-associated protein (BLCAP) transcript in acute lymphoblastic leukemia cells. The results demonstrated that SG could be incorporated into various RNA species, with mRNA having the most abundant SG. In addition, the results showed 6TG treatment elevated A-to-I editing in BLCAP transcript through upregulating adenosine deaminase 2 acting on RNA (ADAR2), which eventually contributes to the decreased cell viability. This study highlights a new mechanism of the cytotoxicity of 6TG in inducing cell death.
6-Thioguanine (6TG) is a widely used chemotherapeutic agent for the treatment of a variety of human diseases including acute lymphoblastic leukemia. After entry into cells, 6TG is metabolically converted into 6-thioguanosine (SG) nucleotide that can be incorporated into the genome during DNA replication. SG in genomic DNA could induce cell death by triggering the post-replicative mismatch repair (MMR) pathway. Meanwhile, incorporation of 6TG into the CpG sites could perturb the global DNA methylation and gene regulation. However, the effect of 6TG on RNA modifications is still unknown. Adenosine-to-inosine (A-to-I) editing in RNA is one of the most common post-transcriptional modifications in mammals and there is growing evidence showing the significant alteration of A-to-I RNA editing in tumor tissues compared to normal tissues. In the current study, we examined the incorporation of 6TG into RNA and investigated its effect on A-to-I editing of bladder cancer-associated protein (BLCAP) transcript in acute lymphoblastic leukemia cells. The results demonstrated that SG could be incorporated into various RNA species, with mRNA having the most abundant SG. In addition, the results showed 6TG treatment elevated A-to-I editing in BLCAP transcript through upregulating adenosine deaminase 2 acting on RNA (ADAR2), which eventually contributes to the decreased cell viability. This study highlights a new mechanism of the cytotoxicity of 6TG in inducing cell death.
2023, 34(1): 107185
doi: 10.1016/j.cclet.2022.01.078
Abstract:
Derivative-extremum analysis (DEA) of j-E curves is a newly proposed method of half wave potential (E1/2) and activation feature extraction from steady-state voltammetry. Here, the DEA is demonstrated to be valid in the full range of reversibility using numerical simulations with a derived universal electrode equation, providing a novel perspective of electrochemical kinetics in the reversibility domain. The results reveal that E1/2 is a better choice of the reference potential instead of equilibrium potential (Eeq) in electrode equations, especially since Eeq is meaningless in an irreversible case. The equations referenced with standard potential, E1/2 and Eeq, are summarized in three tables, and their applications in parameter determinations are specified. Finally, reversibility is proved to be a relative measure between kinetic slowness and mass transport of electroactive species, and the reversibility classifications are proposed according to the DEA feature in the reversibility domain. This work, based on the DEA principle, refines the electrode equation forms and generalizes their applicability in the full range of reversibility.
Derivative-extremum analysis (DEA) of j-E curves is a newly proposed method of half wave potential (E1/2) and activation feature extraction from steady-state voltammetry. Here, the DEA is demonstrated to be valid in the full range of reversibility using numerical simulations with a derived universal electrode equation, providing a novel perspective of electrochemical kinetics in the reversibility domain. The results reveal that E1/2 is a better choice of the reference potential instead of equilibrium potential (Eeq) in electrode equations, especially since Eeq is meaningless in an irreversible case. The equations referenced with standard potential, E1/2 and Eeq, are summarized in three tables, and their applications in parameter determinations are specified. Finally, reversibility is proved to be a relative measure between kinetic slowness and mass transport of electroactive species, and the reversibility classifications are proposed according to the DEA feature in the reversibility domain. This work, based on the DEA principle, refines the electrode equation forms and generalizes their applicability in the full range of reversibility.
2023, 34(1): 107189
doi: 10.1016/j.cclet.2022.01.082
Abstract:
Manganese dioxide (MnO2), a commonly find oxidant in both natural environment and industrial application, plays a crucial role for various organic compound degradation. Tuning the MnO2 crystal structure is a cost-effective strategy to boost the oxidation reactions, where the challenge remains due to lacking in-depth investigation of the crystal properties. Herein, MnO2 with different crystalline structures (x-MnO2) including α-, β- and δ- was prepared through the hydrothermal synthesis for a typical organic pollutant removal. The structural and degradation analysis indicated that the oxidation capacity was originated from Mn3+ and oxygen vacancies (OVs). The intrinsic relationships between oxidation performance and other physiochemical properties such as morphology and electrochemistry were thoroughly discussed, and positive correlations between oxidation capacity and electrochemical properties were found which eventually led to excellent oxidation performance via modulating the above-mentioned properties. Moreover, the K+ content was determined to be the most crucial role in manipulating the structure properties. This work offers a crystal-level insight into the relationship between the crystal structure and oxidative property, promoting rational design of highly efficient oxidant.
Manganese dioxide (MnO2), a commonly find oxidant in both natural environment and industrial application, plays a crucial role for various organic compound degradation. Tuning the MnO2 crystal structure is a cost-effective strategy to boost the oxidation reactions, where the challenge remains due to lacking in-depth investigation of the crystal properties. Herein, MnO2 with different crystalline structures (x-MnO2) including α-, β- and δ- was prepared through the hydrothermal synthesis for a typical organic pollutant removal. The structural and degradation analysis indicated that the oxidation capacity was originated from Mn3+ and oxygen vacancies (OVs). The intrinsic relationships between oxidation performance and other physiochemical properties such as morphology and electrochemistry were thoroughly discussed, and positive correlations between oxidation capacity and electrochemical properties were found which eventually led to excellent oxidation performance via modulating the above-mentioned properties. Moreover, the K+ content was determined to be the most crucial role in manipulating the structure properties. This work offers a crystal-level insight into the relationship between the crystal structure and oxidative property, promoting rational design of highly efficient oxidant.
2023, 34(1): 107197
doi: 10.1016/j.cclet.2022.02.003
Abstract:
The defect engineering in graphene plays a significant role for the application of gas sensors. In this work, we proposed an efficient method to prepare ultrasensitive gas sensors based on the porous reduced graphene oxide (PRGO). Photo-Fenton etching was carried out on GO nanosheets in a controlled manner to enrich their vacancy defects. The resulting porous graphene oxide (PGO) was then drop-coated on interdigital electrodes and hydrothermal reduced at 180 ℃. Controllable reduction was achieved by varying the water amount. The gas sensor based on PRGO-5 min-6 h exhibited superior sensing and selective performance toward nitrogen dioxide (NO2), with an exceptional high sensitivity up to 12 ppm−1. The theoretical limit of detection is down to 0.66 ppb. The excellent performance could be mainly attributed to the typical vacancy defects of PRGO. Some residue carboxylic groups on the edges could also facilitate the adsorption of polar molecules. The process has a great potential for scalable fabrication of high-performance NO2 gas sensors.
The defect engineering in graphene plays a significant role for the application of gas sensors. In this work, we proposed an efficient method to prepare ultrasensitive gas sensors based on the porous reduced graphene oxide (PRGO). Photo-Fenton etching was carried out on GO nanosheets in a controlled manner to enrich their vacancy defects. The resulting porous graphene oxide (PGO) was then drop-coated on interdigital electrodes and hydrothermal reduced at 180 ℃. Controllable reduction was achieved by varying the water amount. The gas sensor based on PRGO-5 min-6 h exhibited superior sensing and selective performance toward nitrogen dioxide (NO2), with an exceptional high sensitivity up to 12 ppm−1. The theoretical limit of detection is down to 0.66 ppb. The excellent performance could be mainly attributed to the typical vacancy defects of PRGO. Some residue carboxylic groups on the edges could also facilitate the adsorption of polar molecules. The process has a great potential for scalable fabrication of high-performance NO2 gas sensors.
2023, 34(1): 107200
doi: 10.1016/j.cclet.2022.02.006
Abstract:
Although converting the greenhouse gasses carbon dioxide (CO2) into solar fuels is regarded as a convenient means of solar energy storage, the intrinsic mechanism on how the high chemical inertness linear CO2 molecules is activated and converted on a semiconductor oxide is still elusive. Herein, by creating the oxygen vacancies on the typical hexagonal tungsten oxide (WO3), we realize the continuous photo-induced CO2 reduction to selectively produce CO under light irradiation, which was verified by isotope labeling experiment. Detailed oxygen vacancies evolution investigation indicates that light irradiation can simultaneously induce the in-situ formation of oxygen vacancies on hexagonal WO3, and the oxygen vacancies promote the adsorption and activation of CO2 molecules, leading to the CO2 reduction to CO on the hexagonal WO3 via an oxygen vacancies-involved process. Besides, the existence of water further promotes the formation of CO2 reduction intermediate, further promote the CO2 photoreduction. Our work provides insight on the mechanism for converting CO2 into CO under light irradiation.
Although converting the greenhouse gasses carbon dioxide (CO2) into solar fuels is regarded as a convenient means of solar energy storage, the intrinsic mechanism on how the high chemical inertness linear CO2 molecules is activated and converted on a semiconductor oxide is still elusive. Herein, by creating the oxygen vacancies on the typical hexagonal tungsten oxide (WO3), we realize the continuous photo-induced CO2 reduction to selectively produce CO under light irradiation, which was verified by isotope labeling experiment. Detailed oxygen vacancies evolution investigation indicates that light irradiation can simultaneously induce the in-situ formation of oxygen vacancies on hexagonal WO3, and the oxygen vacancies promote the adsorption and activation of CO2 molecules, leading to the CO2 reduction to CO on the hexagonal WO3 via an oxygen vacancies-involved process. Besides, the existence of water further promotes the formation of CO2 reduction intermediate, further promote the CO2 photoreduction. Our work provides insight on the mechanism for converting CO2 into CO under light irradiation.
2023, 34(1): 107201
doi: 10.1016/j.cclet.2022.02.007
Abstract:
Development of adsorbent materials for highly efficient iodine capture is high demand from the perspective of ecological environment and human health. Herein, the two kinds of thiophene-based covalent organic frameworks (COFs) with different morphologies were synthesized by solvothermal reaction using thieno[3, 2-b]thiophene-2, 5-dicarbaldehyde (TT) as the aldehyde monomer and tri(4-aminophenyl)benzene (PB) or tris(4-aminophenyl)amine (PA) as the amino monomer (denoted as PB-TT COF and PA-TT COF) and the as-prepared two heteroatoms-rich COFs possessed many excellent properties, including high thermal stability and abundant binding sites. Among them, PB-TT COF exhibited ultra-high iodine uptake up to 5.97 g/g in vapor, surpassing most of adsorbents previously reported, which was ascribed to its high specific surface (1305.3 m2/g). Interestingly, PA-TT COF with low specific surface (48.6 m2/g) showed good adsorption ability for iodine in cyclohexane solution with uptake value of 750 mg/g, which was 2.38 times higher than that obtained with PB-TT COF due to its unique sheet-like morphology. Besides, the two COFs possessed good reusability, high selectivity and iodine retention ability. Based on experimental results, the adsorption mechanisms of both COFs were studied, revealing that iodine was captured by the physical-chemical adsorption. Furthermore, the both COFs showed excellent adsorption ability in real radioactive seawater treated safely, demonstrating their great potential in real environment.
Development of adsorbent materials for highly efficient iodine capture is high demand from the perspective of ecological environment and human health. Herein, the two kinds of thiophene-based covalent organic frameworks (COFs) with different morphologies were synthesized by solvothermal reaction using thieno[3, 2-b]thiophene-2, 5-dicarbaldehyde (TT) as the aldehyde monomer and tri(4-aminophenyl)benzene (PB) or tris(4-aminophenyl)amine (PA) as the amino monomer (denoted as PB-TT COF and PA-TT COF) and the as-prepared two heteroatoms-rich COFs possessed many excellent properties, including high thermal stability and abundant binding sites. Among them, PB-TT COF exhibited ultra-high iodine uptake up to 5.97 g/g in vapor, surpassing most of adsorbents previously reported, which was ascribed to its high specific surface (1305.3 m2/g). Interestingly, PA-TT COF with low specific surface (48.6 m2/g) showed good adsorption ability for iodine in cyclohexane solution with uptake value of 750 mg/g, which was 2.38 times higher than that obtained with PB-TT COF due to its unique sheet-like morphology. Besides, the two COFs possessed good reusability, high selectivity and iodine retention ability. Based on experimental results, the adsorption mechanisms of both COFs were studied, revealing that iodine was captured by the physical-chemical adsorption. Furthermore, the both COFs showed excellent adsorption ability in real radioactive seawater treated safely, demonstrating their great potential in real environment.
2023, 34(1): 107203
doi: 10.1016/j.cclet.2022.02.009
Abstract:
A dual-readout sensing platform based on two signal transduction channels can integrate the unique advantages of each sensing pattern, compensate for the deficiency in the adaptive capacity, and enable a more convincing performance in analytical applications. Here, we introduce a responsive molecule dye, xylenol orange (XO), to combine with lanthanide terbium ions (Tb3+). The resultant Tb3+-XO complex exhibited tunable optical properties and was used as a novel colorimetric and luminometric dual-readout sensing platform for assaying the anthrax biomarker, dipicolinic acid (DPA). In the presence of Tb3+, the XO solution underwent a color change from yellow to magenta; however, upon adding DPA, the color changed back to yellow immediately, accompanied by the characteristic luminescence emission of Tb3+. Considering the strong affinity between DPA/XO and metal ions, the proposed sensing platform was further employed for the determination and differentiation of certain metal ions using linear discriminant analysis. This convenient dual-readout sensing platform offers several notable features and significantly promotes the application and development of lanthanide-based materials.
A dual-readout sensing platform based on two signal transduction channels can integrate the unique advantages of each sensing pattern, compensate for the deficiency in the adaptive capacity, and enable a more convincing performance in analytical applications. Here, we introduce a responsive molecule dye, xylenol orange (XO), to combine with lanthanide terbium ions (Tb3+). The resultant Tb3+-XO complex exhibited tunable optical properties and was used as a novel colorimetric and luminometric dual-readout sensing platform for assaying the anthrax biomarker, dipicolinic acid (DPA). In the presence of Tb3+, the XO solution underwent a color change from yellow to magenta; however, upon adding DPA, the color changed back to yellow immediately, accompanied by the characteristic luminescence emission of Tb3+. Considering the strong affinity between DPA/XO and metal ions, the proposed sensing platform was further employed for the determination and differentiation of certain metal ions using linear discriminant analysis. This convenient dual-readout sensing platform offers several notable features and significantly promotes the application and development of lanthanide-based materials.
2023, 34(1): 107204
doi: 10.1016/j.cclet.2022.02.010
Abstract:
There is an urgent demand for tuning the selectivity and activity of the photocatalysts to remove co-existent pollutants simultaneously. Herein, we introduced the surficial activity sites into the bismuth oxybromide (BiOBr), including the Bi/Bi-O defects and hetero Cu atoms, and then the higher photocatalytic activity and selectivity of BiOBr were realized for degradation phenol and ciprofloxacin (CIP). It can be found that the Bi/Bi-O defects played more important role in enhancing the photocatalytic activity for degradation of phenol, while the Cu atoms significantly improved the photocatalytic activity for removing CIP. Moreover, the heterogeneous Cu atoms as the activity sites excited the reaction between phenol and CIP even under dark condition and were beneficial for synchronously removing phenol and CIP. This work provides a feasible way for BiOX photocatalyst to remove co-existent pollutants and may have a practical application.
There is an urgent demand for tuning the selectivity and activity of the photocatalysts to remove co-existent pollutants simultaneously. Herein, we introduced the surficial activity sites into the bismuth oxybromide (BiOBr), including the Bi/Bi-O defects and hetero Cu atoms, and then the higher photocatalytic activity and selectivity of BiOBr were realized for degradation phenol and ciprofloxacin (CIP). It can be found that the Bi/Bi-O defects played more important role in enhancing the photocatalytic activity for degradation of phenol, while the Cu atoms significantly improved the photocatalytic activity for removing CIP. Moreover, the heterogeneous Cu atoms as the activity sites excited the reaction between phenol and CIP even under dark condition and were beneficial for synchronously removing phenol and CIP. This work provides a feasible way for BiOX photocatalyst to remove co-existent pollutants and may have a practical application.
2023, 34(1): 107207
doi: 10.1016/j.cclet.2022.02.013
Abstract:
To investigate the reactivity of homoatomic clusters [E9]4− (E = Si-Pb) and intermetalloid clusters [M@E9]−, the reactions of the Zintl anions [Sn9]4− and [Ni@Sn9]4− with the CdMes2 (Mes = Mesitylene) in the presence of 2.2.2-crypt were carried out. Two new compounds [K(2.2.2-crypt)]6[(Sn9)Cd(Sn9)]·en (1) and [K(2.2.2-crypt)]6[(Ni@Sn9)Cd(Ni@Sn9)]·en (2) were afforded. Both 1 and 2 were characterized by single-crystal X-ray diffraction, energy dispersive X-ray (EDX), and electrospray ionization mass spectrometry (ESI-MS), and can be viewed as two [Sn9]4− or [Ni@Sn9]4− subunits bridged by Cd ion in an η3: η3 coordination mode. Quantum chemical calculations reveal the relationships between the geometries and electronic structures of clusters 2a, [Ni3Ge18]4− and [Cu4@Sn18]4−. Further electron localization technique (AdNDP method) was performed to explain chemical bonding patterns of 1a.
To investigate the reactivity of homoatomic clusters [E9]4− (E = Si-Pb) and intermetalloid clusters [M@E9]−, the reactions of the Zintl anions [Sn9]4− and [Ni@Sn9]4− with the CdMes2 (Mes = Mesitylene) in the presence of 2.2.2-crypt were carried out. Two new compounds [K(2.2.2-crypt)]6[(Sn9)Cd(Sn9)]·en (1) and [K(2.2.2-crypt)]6[(Ni@Sn9)Cd(Ni@Sn9)]·en (2) were afforded. Both 1 and 2 were characterized by single-crystal X-ray diffraction, energy dispersive X-ray (EDX), and electrospray ionization mass spectrometry (ESI-MS), and can be viewed as two [Sn9]4− or [Ni@Sn9]4− subunits bridged by Cd ion in an η3: η3 coordination mode. Quantum chemical calculations reveal the relationships between the geometries and electronic structures of clusters 2a, [Ni3Ge18]4− and [Cu4@Sn18]4−. Further electron localization technique (AdNDP method) was performed to explain chemical bonding patterns of 1a.
2023, 34(1): 107208
doi: 10.1016/j.cclet.2022.02.014
Abstract:
Simulating the structures and behaviors of living organisms are of great significance to develop novel multi-functional intelligent devices. However, the development of biomimetic devices with complex deformable structures and synergistic properties is still on the way. Herein, we propose a simple and effective approach to create the multi-functional stimuli-responsive biomimetic devices with independently pre-programmable colorful visual patterns, complex geometries and morphable modes. The metal organic framework (MOF)-based composite film acts as a rigidity actuation substrate to support and mechanically guide the spatial configuration of the soft chiral nematic liquid crystal elastomer (CLCE) sheet. We can directly program the structural color of the CLCE sheet by adjusting the thickness distribution without tedious chemical modification. By using this coordination strategy, we fabricate an artificial flower, which exhibits a synergistic effect of both shape transformation and color change like paeonia 'Coral Sunset' at different flowering stages, and can even perform different flowering behaviors by bending, twisting and curling petals. The assembled bionic flower is innovatively demonstrated to respond to local stimuli of humidity, heat or ultraviolet irradiation. Therefore, the spatial assembly of CLCE combined with functional MOF materials has a wide range of potential application in multi-functional integrated artificial systems.
Simulating the structures and behaviors of living organisms are of great significance to develop novel multi-functional intelligent devices. However, the development of biomimetic devices with complex deformable structures and synergistic properties is still on the way. Herein, we propose a simple and effective approach to create the multi-functional stimuli-responsive biomimetic devices with independently pre-programmable colorful visual patterns, complex geometries and morphable modes. The metal organic framework (MOF)-based composite film acts as a rigidity actuation substrate to support and mechanically guide the spatial configuration of the soft chiral nematic liquid crystal elastomer (CLCE) sheet. We can directly program the structural color of the CLCE sheet by adjusting the thickness distribution without tedious chemical modification. By using this coordination strategy, we fabricate an artificial flower, which exhibits a synergistic effect of both shape transformation and color change like paeonia 'Coral Sunset' at different flowering stages, and can even perform different flowering behaviors by bending, twisting and curling petals. The assembled bionic flower is innovatively demonstrated to respond to local stimuli of humidity, heat or ultraviolet irradiation. Therefore, the spatial assembly of CLCE combined with functional MOF materials has a wide range of potential application in multi-functional integrated artificial systems.
2023, 34(1): 107213
doi: 10.1016/j.cclet.2022.02.018
Abstract:
The production of CH3COOH from CO2 and CH4 has stimulated much interest due to the high energy density of C2 species. Various kinds of catalysts have been developed while the high dissociation barrier of CH4 and low selectivity still hinders the efficiency of the reaction. We have herein proposed a novel catalyst with single metals loaded on 2D BC3N2 substrate (M@2D-BC3N2) based on density functional theory. Among numerous candidates, Pt@2D-BC3N2 possesses the most favorable reactivity with an ultralow barrier of CH4 splitting (0.26 eV), which is due to the efficient capture ability of CH4 on Pt site. Besides, the selectivity for CH3COOH is also very high, which mainly stems from the unique electronic properties of molecules and substrate: The degenerated states, including s, px, py and pz, in CO2 reflects the existence of delocalized π bonds between C and O. This can interact with states of Pt(s), Pt(pz), Pt(dxz), Pt(dyz), and Pt(z2) in Pt@2D-BC3N2. The kinetics model also proves that our system can promote CH3COOH production via simply increasing the temperature or the coverage of CH4 and CO2. Our results provide a reasonable illustration in clarifying mechanism and propose promising candidates with high reactivity for further study.
The production of CH3COOH from CO2 and CH4 has stimulated much interest due to the high energy density of C2 species. Various kinds of catalysts have been developed while the high dissociation barrier of CH4 and low selectivity still hinders the efficiency of the reaction. We have herein proposed a novel catalyst with single metals loaded on 2D BC3N2 substrate (M@2D-BC3N2) based on density functional theory. Among numerous candidates, Pt@2D-BC3N2 possesses the most favorable reactivity with an ultralow barrier of CH4 splitting (0.26 eV), which is due to the efficient capture ability of CH4 on Pt site. Besides, the selectivity for CH3COOH is also very high, which mainly stems from the unique electronic properties of molecules and substrate: The degenerated states, including s, px, py and pz, in CO2 reflects the existence of delocalized π bonds between C and O. This can interact with states of Pt(s), Pt(pz), Pt(dxz), Pt(dyz), and Pt(z2) in Pt@2D-BC3N2. The kinetics model also proves that our system can promote CH3COOH production via simply increasing the temperature or the coverage of CH4 and CO2. Our results provide a reasonable illustration in clarifying mechanism and propose promising candidates with high reactivity for further study.
2023, 34(1): 107216
doi: 10.1016/j.cclet.2022.02.021
Abstract:
Herein, phosphorus-mediated sulfur nanoparticles encapsulated in reduced graphene oxide nanosheets (P-SrGO-T) were successfully synthesized as the cathode for sodium ion battery by a ball milling and the following thermal treatment. A series of covalent bonds, such as P–S, C–S–C, C–O–P and C–S–P, are formed in this process, which are in favor of fixing the sulfur and suppressing the parasitic shuttle effect of polysulfide. Benefiting from the graphene sheets and these covalent bonds, a high reversible capacity of 637.4 mAh/g was achieved in P-SrGO-T after 100 cycles at the current density of 0.2 A/g. In addition, P-SrGO-T also delivers a high-rate capacity (330.7 mAh/g at 5 A/g) attributing to low charge transfer resistance and faster ion diffusion kinetic. This work pushes the progress forward in developing phosphosulfide cathode for sodium ion batteries.
Herein, phosphorus-mediated sulfur nanoparticles encapsulated in reduced graphene oxide nanosheets (P-SrGO-T) were successfully synthesized as the cathode for sodium ion battery by a ball milling and the following thermal treatment. A series of covalent bonds, such as P–S, C–S–C, C–O–P and C–S–P, are formed in this process, which are in favor of fixing the sulfur and suppressing the parasitic shuttle effect of polysulfide. Benefiting from the graphene sheets and these covalent bonds, a high reversible capacity of 637.4 mAh/g was achieved in P-SrGO-T after 100 cycles at the current density of 0.2 A/g. In addition, P-SrGO-T also delivers a high-rate capacity (330.7 mAh/g at 5 A/g) attributing to low charge transfer resistance and faster ion diffusion kinetic. This work pushes the progress forward in developing phosphosulfide cathode for sodium ion batteries.
2023, 34(1): 107221
doi: 10.1016/j.cclet.2022.02.026
Abstract:
Formic acid decomposition (FAD) is considered a promising hydrogen production route to facilitate the ambient storage and on demand release of hydrogen energy. To optimize the catalysts for FAD, efforts have been paid to explore the underlying reason for the varied catalytic activity among catalysts with similar composition but differed structure. However, such endeavors are highly challenging due to the deeply intermingled effects of electronic structure, particle size, and facets, etc. Herein, to separately evaluate the respective effects of these factors, a series of catalysts with the same surface electronic structure and different particle size was prepared by cation dipole adjustment method. The performance and characterization results showed that the catalysts with different sizes and facets exhibited similar intrinsic activity with deviation of less than 5%. However, they showed 252% deviation of site stability, indicating that only the optimized electronic structure could enhance the intrinsic activity and a smaller particle size could extend the catalyst's life.
Formic acid decomposition (FAD) is considered a promising hydrogen production route to facilitate the ambient storage and on demand release of hydrogen energy. To optimize the catalysts for FAD, efforts have been paid to explore the underlying reason for the varied catalytic activity among catalysts with similar composition but differed structure. However, such endeavors are highly challenging due to the deeply intermingled effects of electronic structure, particle size, and facets, etc. Herein, to separately evaluate the respective effects of these factors, a series of catalysts with the same surface electronic structure and different particle size was prepared by cation dipole adjustment method. The performance and characterization results showed that the catalysts with different sizes and facets exhibited similar intrinsic activity with deviation of less than 5%. However, they showed 252% deviation of site stability, indicating that only the optimized electronic structure could enhance the intrinsic activity and a smaller particle size could extend the catalyst's life.
2023, 34(1): 107229
doi: 10.1016/j.cclet.2022.02.034
Abstract:
Lithium-sulfur batteries (LSBs) are among the most promising series of next-generation high density energy storage systems. However, the problem of "shuttle effect" caused by dissolution and migration of polysulfide intermediates has severely inhibited their practical applications. Herein, TiO2-carbon nanocomposites embedded hierarchical porous carbon (T-hPC) interlayers are fabricated via Ti3C2 MXene assisted phase separation and annealing method. The T-hPC processes micro- to macro-scale multi-pores along with highly adsorptive and catalytic carbon supported TiO2 nanoparticles, which significantly enhances the polysulfides immobilization and improves the redox reaction kinetics when applied as lithium-sulfur battery interlayers. An initial discharge specific capacity of 1551.1 mAh/g and a stable capacity of 893.8 mAh/g after 200 cycles at 0.5 C are obtained, corresponding to a capacity decay rate of only 0.04% per cycle. The investigations in this paper can provide a simple and effective strategy to enhance the electrochemical properties for lithium-sulfur batteries.
Lithium-sulfur batteries (LSBs) are among the most promising series of next-generation high density energy storage systems. However, the problem of "shuttle effect" caused by dissolution and migration of polysulfide intermediates has severely inhibited their practical applications. Herein, TiO2-carbon nanocomposites embedded hierarchical porous carbon (T-hPC) interlayers are fabricated via Ti3C2 MXene assisted phase separation and annealing method. The T-hPC processes micro- to macro-scale multi-pores along with highly adsorptive and catalytic carbon supported TiO2 nanoparticles, which significantly enhances the polysulfides immobilization and improves the redox reaction kinetics when applied as lithium-sulfur battery interlayers. An initial discharge specific capacity of 1551.1 mAh/g and a stable capacity of 893.8 mAh/g after 200 cycles at 0.5 C are obtained, corresponding to a capacity decay rate of only 0.04% per cycle. The investigations in this paper can provide a simple and effective strategy to enhance the electrochemical properties for lithium-sulfur batteries.
2023, 34(1): 107236
doi: 10.1016/j.cclet.2022.02.041
Abstract:
Fe-N/C is a promising oxygen reduction reaction (ORR) catalyst to substitute the current widely used precious metal platinum. Cost-effectively fabricating the Fe-N/C material with high catalytic activity and getting in-depth insight into the responsible catalytic site are of great significance. In this work, we proposed to use biomass, tea leaves waste, as the precursor to prepare ORR catalyst. By adding 5% FeCl3 (wt%) into tea precursor, the pyrolysis product (i.e., 5%Fe-N/C) exhibited an excellent four-electron ORR activity, whose onset potential was only 10 mV lower than that of commercial Pt/C. The limiting current density of 5%Fe-N/C (5.75 mA/cm2) was even higher than Pt/C (5.44 mA/cm2). Compared with other biomass or metal organic frameworks derived catalysts, 5%Fe-N/C showed similar ORR activity. Also, both the methanol tolerance and material stability performances of as-prepared 5%Fe-N/C catalyst were superior to that of Pt/C. X-ray adsorption fine structure characterization revealed that the FeN4O2 might be the possible catalytic site. An appropriate amount of iron chloride addition not only facilitated catalytic site formation, but also enhanced material conductivity and reaction kinetics. The results of this work may be useful for the Fe based transition metal ORR catalyst design and application.
Fe-N/C is a promising oxygen reduction reaction (ORR) catalyst to substitute the current widely used precious metal platinum. Cost-effectively fabricating the Fe-N/C material with high catalytic activity and getting in-depth insight into the responsible catalytic site are of great significance. In this work, we proposed to use biomass, tea leaves waste, as the precursor to prepare ORR catalyst. By adding 5% FeCl3 (wt%) into tea precursor, the pyrolysis product (i.e., 5%Fe-N/C) exhibited an excellent four-electron ORR activity, whose onset potential was only 10 mV lower than that of commercial Pt/C. The limiting current density of 5%Fe-N/C (5.75 mA/cm2) was even higher than Pt/C (5.44 mA/cm2). Compared with other biomass or metal organic frameworks derived catalysts, 5%Fe-N/C showed similar ORR activity. Also, both the methanol tolerance and material stability performances of as-prepared 5%Fe-N/C catalyst were superior to that of Pt/C. X-ray adsorption fine structure characterization revealed that the FeN4O2 might be the possible catalytic site. An appropriate amount of iron chloride addition not only facilitated catalytic site formation, but also enhanced material conductivity and reaction kinetics. The results of this work may be useful for the Fe based transition metal ORR catalyst design and application.
2023, 34(1): 107237
doi: 10.1016/j.cclet.2022.02.042
Abstract:
The development of effective Ru catalyst for ammonia synthesis is of important practical value and scientific significance because of the wide application of ammonia as a fertilizer and its promising applications in the renewable energy. Generally, ZrO2 was regarded as an inferior support for Ru catalyst used in ammonia synthesis. Here we prepare ZrO2 with monoclinic phase and carbon species from ZrCl4 following the preparation route of UiO-66 as well as ammonia treatment. Owing to the presence of a larger amount of hydrogen adsorption as well as the easier desorption of hydrogen species, the ill effect of hydrogen species on the nitrogen adsorption-desorption and ammonia synthesis can be effectively alleviated. The resulting ZrO2-supported Ru catalyst showed 4 times higher ammonia synthesis activity than the conventional Ru/ZrO2 obtained from zirconium nitrate.
The development of effective Ru catalyst for ammonia synthesis is of important practical value and scientific significance because of the wide application of ammonia as a fertilizer and its promising applications in the renewable energy. Generally, ZrO2 was regarded as an inferior support for Ru catalyst used in ammonia synthesis. Here we prepare ZrO2 with monoclinic phase and carbon species from ZrCl4 following the preparation route of UiO-66 as well as ammonia treatment. Owing to the presence of a larger amount of hydrogen adsorption as well as the easier desorption of hydrogen species, the ill effect of hydrogen species on the nitrogen adsorption-desorption and ammonia synthesis can be effectively alleviated. The resulting ZrO2-supported Ru catalyst showed 4 times higher ammonia synthesis activity than the conventional Ru/ZrO2 obtained from zirconium nitrate.
2023, 34(1): 107248
doi: 10.1016/j.cclet.2022.02.053
Abstract:
Transition metal hydroxides/oxyhydroxides have recently emerged as highly active electrocatalysts for oxygen evolution reaction in alkaline water electrolysis, while have not yet been widely investigated for hydrogen evolution electrocatalysts owing to their unfavorable H*-adsorption, making it difficult to construct an overall-water-splitting cell for hydrogen production. In this work, we proposed a straightforward and effective approach to develop an efficient in-plane heterostructured CoOOH/Co(OH)2 catalyst via In-situ electrochemical dehydrogenation method, in which the dehydrogenated –CoOOH and Co(OH)2 at the surface synergistically boost the hydrogen evolution reaction (HER) kinetics in base as confirmed by high-resolution transmission electron microscope, synchrotron X-ray absorption spectroscopy, and electron energy loss spectroscopy. Due to the In-situ dehydrogenation of ultrathin Co(OH)2 nanosheets, the catalytic activity of the CoOOH/Co(OH)2 heterostructures is progressively improved, which exhibit outstanding hydrogen-evolving activity in base requiring a low overpotential of 132 mV to afford 10 mA/cm2 with very fast reaction kinetics after 60 h dehydrogenation. The gradually improved catalytic performance for the CoOOH/Co(OH)2 is probably due to the enhanced H*-adsorption induced by the synergistic effect of heterostructures and better conductivity of CoOOH relative to electrically insulating Co(OH)2. This work will open the opportunity for a new family of transition metal hydroxides/oxyhydroxides as active HER catalysts, and also highlight the importance of using in situ techniques to construct precious metal-free efficient catalysts for alkaline hydrogen evolution.
Transition metal hydroxides/oxyhydroxides have recently emerged as highly active electrocatalysts for oxygen evolution reaction in alkaline water electrolysis, while have not yet been widely investigated for hydrogen evolution electrocatalysts owing to their unfavorable H*-adsorption, making it difficult to construct an overall-water-splitting cell for hydrogen production. In this work, we proposed a straightforward and effective approach to develop an efficient in-plane heterostructured CoOOH/Co(OH)2 catalyst via In-situ electrochemical dehydrogenation method, in which the dehydrogenated –CoOOH and Co(OH)2 at the surface synergistically boost the hydrogen evolution reaction (HER) kinetics in base as confirmed by high-resolution transmission electron microscope, synchrotron X-ray absorption spectroscopy, and electron energy loss spectroscopy. Due to the In-situ dehydrogenation of ultrathin Co(OH)2 nanosheets, the catalytic activity of the CoOOH/Co(OH)2 heterostructures is progressively improved, which exhibit outstanding hydrogen-evolving activity in base requiring a low overpotential of 132 mV to afford 10 mA/cm2 with very fast reaction kinetics after 60 h dehydrogenation. The gradually improved catalytic performance for the CoOOH/Co(OH)2 is probably due to the enhanced H*-adsorption induced by the synergistic effect of heterostructures and better conductivity of CoOOH relative to electrically insulating Co(OH)2. This work will open the opportunity for a new family of transition metal hydroxides/oxyhydroxides as active HER catalysts, and also highlight the importance of using in situ techniques to construct precious metal-free efficient catalysts for alkaline hydrogen evolution.
2023, 34(1): 107253
doi: 10.1016/j.cclet.2022.02.058
Abstract:
This study explored the catalytic mechanism and performance impacted by the materials ratio of Fe3O4-GOx composites in three typical advanced oxidation processes (AOPs) of O3, peroxodisulfate (PDS) and photo-Fenton processes for tetracycline hydrochloride (TCH) degradation. The ratio of GO in the Fe3O4-GOx composites exhibited different trends of degradation capacity in each AOPs based on different mechanisms. Fe3O4-rGO20wt% exhibited the optimum catalytic performance which enhanced the ozone decomposition efficiency from 33.48% (ozone alone) to 51.83% with the major reactive oxygen species (ROS) of O2•−. In PDS and photo-Fenton processes, Fe3O4-rGO5wt% had the highest catalytic performance in PDS and H2O2 decomposition for SO4•‒, and •OH generation, respectively. Compared with using PDS alone, PDS decomposition rate and TCH degradation rate could be increased by 5.97 and 1.73 times under Fe3O4-rGO5wt% catalysis. In the photo-Fenton system, Fe3O4-rGO5wt% with the best catalyst performance in H2O2 decomposition, and TCH degradation rate increased by 2.02 times compared with blank group. Meantime, the catalytic mechanisms in those systems of that the ROS produced by conversion between Fe2+/Fe3+ were also analyzed.
This study explored the catalytic mechanism and performance impacted by the materials ratio of Fe3O4-GOx composites in three typical advanced oxidation processes (AOPs) of O3, peroxodisulfate (PDS) and photo-Fenton processes for tetracycline hydrochloride (TCH) degradation. The ratio of GO in the Fe3O4-GOx composites exhibited different trends of degradation capacity in each AOPs based on different mechanisms. Fe3O4-rGO20wt% exhibited the optimum catalytic performance which enhanced the ozone decomposition efficiency from 33.48% (ozone alone) to 51.83% with the major reactive oxygen species (ROS) of O2•−. In PDS and photo-Fenton processes, Fe3O4-rGO5wt% had the highest catalytic performance in PDS and H2O2 decomposition for SO4•‒, and •OH generation, respectively. Compared with using PDS alone, PDS decomposition rate and TCH degradation rate could be increased by 5.97 and 1.73 times under Fe3O4-rGO5wt% catalysis. In the photo-Fenton system, Fe3O4-rGO5wt% with the best catalyst performance in H2O2 decomposition, and TCH degradation rate increased by 2.02 times compared with blank group. Meantime, the catalytic mechanisms in those systems of that the ROS produced by conversion between Fe2+/Fe3+ were also analyzed.
2023, 34(1): 107255
doi: 10.1016/j.cclet.2022.02.060
Abstract:
Solid-state materials that exhibit pressure stimulus-response characteristics in a manner of emission signal, known as piezochromic luminescence (PCL), demonstrate great potential in photoelectric devices. The weakened luminescence and insignificant color change in the aggregation state, however, hampers their practical applications. Herein, a highly emissive coordination polymer, [Zn2(H4TTPE)(H2O)4]·H2O (CUST-805), is successfully constructed by employing an AIE-active chromophore as the building block. The structural characterization and photophysical properties are systematically studied. Owing to intrinsic twisted conformation and AIE feature of tetraphenylethylene-tetrazole ligand, CUST-805 achieves the visible and reversible PCL from blue to green switched by different external stimuli. The transformation between crystalline and amorphous states is proved to be the origin of present PCL behavior. Moreover, on basis of electron and energy transfer quenching mechanism, the highly selective and sensitive sensor based on CUST-805 is realized, showing the low detection limit of 0.29 ppm towards 2, 4, 6-trinitrophenol.
Solid-state materials that exhibit pressure stimulus-response characteristics in a manner of emission signal, known as piezochromic luminescence (PCL), demonstrate great potential in photoelectric devices. The weakened luminescence and insignificant color change in the aggregation state, however, hampers their practical applications. Herein, a highly emissive coordination polymer, [Zn2(H4TTPE)(H2O)4]·H2O (CUST-805), is successfully constructed by employing an AIE-active chromophore as the building block. The structural characterization and photophysical properties are systematically studied. Owing to intrinsic twisted conformation and AIE feature of tetraphenylethylene-tetrazole ligand, CUST-805 achieves the visible and reversible PCL from blue to green switched by different external stimuli. The transformation between crystalline and amorphous states is proved to be the origin of present PCL behavior. Moreover, on basis of electron and energy transfer quenching mechanism, the highly selective and sensitive sensor based on CUST-805 is realized, showing the low detection limit of 0.29 ppm towards 2, 4, 6-trinitrophenol.
2023, 34(1): 107259
doi: 10.1016/j.cclet.2022.02.064
Abstract:
Fungal infections are hazardous to human health that has drawn wide attention. In this work, a specific and sensitive method combing the recognition of aptamer to (1, 3)-β-D-glucan and tyramide signal amplification technology was proposed for the in situ fluorescence imaging of fungi. Fungi could be distinctly observed by fluorescence microscope rapidly. This method provides morphology and diagnostic information for identifying fungi. The combination of aptamer and tyramide signal amplification technology is a promising tool for the detection of fungi, bacteria and even eukaryotic cell with the virtue of biomarkers.
Fungal infections are hazardous to human health that has drawn wide attention. In this work, a specific and sensitive method combing the recognition of aptamer to (1, 3)-β-D-glucan and tyramide signal amplification technology was proposed for the in situ fluorescence imaging of fungi. Fungi could be distinctly observed by fluorescence microscope rapidly. This method provides morphology and diagnostic information for identifying fungi. The combination of aptamer and tyramide signal amplification technology is a promising tool for the detection of fungi, bacteria and even eukaryotic cell with the virtue of biomarkers.
2023, 34(1): 107262
doi: 10.1016/j.cclet.2022.02.067
Abstract:
The transformation of quantum dots (QDs) by organisms has attracted broad attention but remains unclear. Understanding of the metabolites helps to reveal the transformation pathway of QDs. Cd containing-metallothionein (MT) are the main species formed by Cd released from CdSe QDs in HepG2 cells, while speciation analysis of Cd containing MTs remains a challenge because MTs has several subisoforms and can bind with several metals. Herein, we built a hyphenated platform for speciation analysis of QDs in HepG2 cells after treatment with CdSe/ZnS QDs. The Cd-containing MTs were separated in reversed phase high performance liquid chromatography (RP-HPLC) and subsequently online detected by inductively coupled plasma mass spectrometry (ICP-MS) and electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-Q-TOF-MS) parallelly. Four groups of Cd-containing metabolites were found by detecting Cd in ICP-MS. Their structures were identified in ESI-Q-TOF-MS and further confirmed with standards of four subisoforms of MT, including N-terminal acetylation MT2a, N-terminal acetylation MT1e, N-terminal acetylation MT1g and MT1m. Each group of them contains various stoichiometry of Cd/Zn. The metabolites of QDs remain same while the concentrations of each metabolite and its stoichiometry of Cd/Zn vary for different incubation concentration/time. This work provides a new parallel hyphenation technique of HPLC-ICP-MS/ESI-MS with high separation resolution and powerful detection ability, and the obtained results provide detailed metabolism information of QDs in HepG2 cells after treatment of CdSe/ZnS QDs, contributing to deep exploration of the functional mechanisms of QDs in organisms.
The transformation of quantum dots (QDs) by organisms has attracted broad attention but remains unclear. Understanding of the metabolites helps to reveal the transformation pathway of QDs. Cd containing-metallothionein (MT) are the main species formed by Cd released from CdSe QDs in HepG2 cells, while speciation analysis of Cd containing MTs remains a challenge because MTs has several subisoforms and can bind with several metals. Herein, we built a hyphenated platform for speciation analysis of QDs in HepG2 cells after treatment with CdSe/ZnS QDs. The Cd-containing MTs were separated in reversed phase high performance liquid chromatography (RP-HPLC) and subsequently online detected by inductively coupled plasma mass spectrometry (ICP-MS) and electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-Q-TOF-MS) parallelly. Four groups of Cd-containing metabolites were found by detecting Cd in ICP-MS. Their structures were identified in ESI-Q-TOF-MS and further confirmed with standards of four subisoforms of MT, including N-terminal acetylation MT2a, N-terminal acetylation MT1e, N-terminal acetylation MT1g and MT1m. Each group of them contains various stoichiometry of Cd/Zn. The metabolites of QDs remain same while the concentrations of each metabolite and its stoichiometry of Cd/Zn vary for different incubation concentration/time. This work provides a new parallel hyphenation technique of HPLC-ICP-MS/ESI-MS with high separation resolution and powerful detection ability, and the obtained results provide detailed metabolism information of QDs in HepG2 cells after treatment of CdSe/ZnS QDs, contributing to deep exploration of the functional mechanisms of QDs in organisms.
2023, 34(1): 107273
doi: 10.1016/j.cclet.2022.02.078
Abstract:
In this study, through direct pyrolysis of a nitrogen-rich metal-organic framework of Fe-BTT at different temperatures and followed by acid treatment, we prepared a series of Fe–N–CT (T = 800–1000 ℃) composite catalysts with uniform cubic morphology and homogeneously distributed active sites. Acid leaching leads to the removal of excess Fe NPs and the exposure of more pyridinic N and porphyrin-like Fe–Nx sites and creates a higher specific surface area. Structural and electrochemical performance test results showed that Fe–N–C900 catalyst exhibited the highest selectivity for CO product at –1.2 V vs. Ag/AgCl, with 496 mV of overpotential and 86.8% of Faraday efficiency, as well as excellent long-term stability, due to the good inheritance from rich-N Fe–BTT precursor.
In this study, through direct pyrolysis of a nitrogen-rich metal-organic framework of Fe-BTT at different temperatures and followed by acid treatment, we prepared a series of Fe–N–CT (T = 800–1000 ℃) composite catalysts with uniform cubic morphology and homogeneously distributed active sites. Acid leaching leads to the removal of excess Fe NPs and the exposure of more pyridinic N and porphyrin-like Fe–Nx sites and creates a higher specific surface area. Structural and electrochemical performance test results showed that Fe–N–C900 catalyst exhibited the highest selectivity for CO product at –1.2 V vs. Ag/AgCl, with 496 mV of overpotential and 86.8% of Faraday efficiency, as well as excellent long-term stability, due to the good inheritance from rich-N Fe–BTT precursor.
2023, 34(1): 107282
doi: 10.1016/j.cclet.2022.03.005
Abstract:
NH3 plays an essential role in human life since it is an important raw material for fertilizers, plastics and rubbers production. As an NH3 synthesis technology under ambient conditions, electrocatalytic N2 reduction reaction (NRR) has great potential to replace the energy-intensive Haber-Bosch process. The key of electrocatalytic NRR is the exploration of efficient catalysts. Transition metal Mo is promising since it exists naturally in nitrogenase due to the unique Mo-N2 interaction; particularly in the form of 2D material such as MoSe2, the surface area is maximized for more active sites. However, the NRR performance of MoSe2 is still unsatisfactory because Mo is only exposed at the semi-open edge, and the electronegative Se-mantled surface area remains inaccessible to N2. Herein, we propose a simple and effective strategy to create high-concentration Se vacancies in MoSe2 through heteroatom doping induced lattice strain, which effectively enhances the Mo-N2 interaction on the surface area. In result, high NH3 yield (3.04 × 10–10 mol s–1 cm–2) and Faraday efficiency (21.61%) are attained at –0.45 V vs. RHE in 0.1 mol/L Na2SO4.
NH3 plays an essential role in human life since it is an important raw material for fertilizers, plastics and rubbers production. As an NH3 synthesis technology under ambient conditions, electrocatalytic N2 reduction reaction (NRR) has great potential to replace the energy-intensive Haber-Bosch process. The key of electrocatalytic NRR is the exploration of efficient catalysts. Transition metal Mo is promising since it exists naturally in nitrogenase due to the unique Mo-N2 interaction; particularly in the form of 2D material such as MoSe2, the surface area is maximized for more active sites. However, the NRR performance of MoSe2 is still unsatisfactory because Mo is only exposed at the semi-open edge, and the electronegative Se-mantled surface area remains inaccessible to N2. Herein, we propose a simple and effective strategy to create high-concentration Se vacancies in MoSe2 through heteroatom doping induced lattice strain, which effectively enhances the Mo-N2 interaction on the surface area. In result, high NH3 yield (3.04 × 10–10 mol s–1 cm–2) and Faraday efficiency (21.61%) are attained at –0.45 V vs. RHE in 0.1 mol/L Na2SO4.
2023, 34(1): 107286
doi: 10.1016/j.cclet.2022.03.009
Abstract:
A novel atmospheric pressure matrix-assisted laser desorption ionization mass spectrometry (AP-MALDI-MS) method was established for the facile detection of pesticides in ambient environment. Four kinds of multi-walled carbon nanotubes (MWCNTs)-based matrix were synthesized and utilized to enhance the ionization efficiency of pesticides. Organophosphorus, anilinopyrimidine, carbamate, triazine, triazole and benzimidazole pesticides were directly desorbed and ionized from MWCNTs-based matrix in ambient environment, showing clear background and good sensitivity. In a comparison, Fe3O4-doped MWCNTs improved the intensity of pesticide ions more than the other three matrices. Moreover, MWCNTs-based matrix exhibited better performance than organic matrix. Quantitative analysis of pesticides using AP-MALDI-MS was validated to be adequate linearity, repeatability and sensitivity. Overall, AP-MALDI-MS combined with MWCNTs-based matrix enables the directly qualitative and quantitative analysis of pesticides in ambient environment.
A novel atmospheric pressure matrix-assisted laser desorption ionization mass spectrometry (AP-MALDI-MS) method was established for the facile detection of pesticides in ambient environment. Four kinds of multi-walled carbon nanotubes (MWCNTs)-based matrix were synthesized and utilized to enhance the ionization efficiency of pesticides. Organophosphorus, anilinopyrimidine, carbamate, triazine, triazole and benzimidazole pesticides were directly desorbed and ionized from MWCNTs-based matrix in ambient environment, showing clear background and good sensitivity. In a comparison, Fe3O4-doped MWCNTs improved the intensity of pesticide ions more than the other three matrices. Moreover, MWCNTs-based matrix exhibited better performance than organic matrix. Quantitative analysis of pesticides using AP-MALDI-MS was validated to be adequate linearity, repeatability and sensitivity. Overall, AP-MALDI-MS combined with MWCNTs-based matrix enables the directly qualitative and quantitative analysis of pesticides in ambient environment.
2023, 34(1): 107298
doi: 10.1016/j.cclet.2022.03.021
Abstract:
Photocatalytic selective transform native lignin into valuable chemicals is an attractive but challenging task. Herein, we report a mesoporous sulfur-doped carbon nitride (MSCN-0.5) which is prepared by a facile one-step thermal condensation strategy. It is highly active and selective for the cleavage Cα−Cβ bond in β−O−4 lignin model compound under visible light radiation at room temperature, achieving 99% substrate conversion and 98% Cα−Cβ bond cleavage selectivity. Mechanistic studies revealed that the Cβ−H bond of lignin model compounds activated by holes and generate key Cβ radical intermediates, further induced the Cα−Cβ bond cleavage by superoxide anion radicals (•O2−) to produce aromatic oxygenates. Waste Camellia oleifera shell (WCOS) was taken as a representative to further understand the reaction mechanisms on native lignin. 33.2 mg of monophenolic compounds (Vanillin accounted for 22% and Syringaldehyde for 34%) can be obtained by each gram of WCOS lignin, which is 2.5 times as that of the pristine carbon nitride. The present work offers useful guidance for designing metal-free heterogeneous photocatalysts for Cα−Cβ bond cleavage to harvest monophenolic compounds.
Photocatalytic selective transform native lignin into valuable chemicals is an attractive but challenging task. Herein, we report a mesoporous sulfur-doped carbon nitride (MSCN-0.5) which is prepared by a facile one-step thermal condensation strategy. It is highly active and selective for the cleavage Cα−Cβ bond in β−O−4 lignin model compound under visible light radiation at room temperature, achieving 99% substrate conversion and 98% Cα−Cβ bond cleavage selectivity. Mechanistic studies revealed that the Cβ−H bond of lignin model compounds activated by holes and generate key Cβ radical intermediates, further induced the Cα−Cβ bond cleavage by superoxide anion radicals (•O2−) to produce aromatic oxygenates. Waste Camellia oleifera shell (WCOS) was taken as a representative to further understand the reaction mechanisms on native lignin. 33.2 mg of monophenolic compounds (Vanillin accounted for 22% and Syringaldehyde for 34%) can be obtained by each gram of WCOS lignin, which is 2.5 times as that of the pristine carbon nitride. The present work offers useful guidance for designing metal-free heterogeneous photocatalysts for Cα−Cβ bond cleavage to harvest monophenolic compounds.
2023, 34(1): 107299
doi: 10.1016/j.cclet.2022.03.022
Abstract:
Boron/nitrogen-co-doped carbon (BCN) nanosheets decorated with Fe2O3 nanocrystals (Fe2O3–BCN) were cast on a glassy carbon electrode (GCE) and applied as an electrochemical sensor to effectively detect paraquat (PQ), a toxic herbicide, in aqueous environments. A linear experiment performed using square wave voltammetry (SWV) under optimized experimental conditions produced a decent linear relationship and a low detection limit (LOD) of 2.74 nmol/L (S/N = 3). Repeatability, reproducibility, stability, and interference experiments confirmed that the Fe2O3–BCN/GCE system exhibited decent electrochemical sensing performance for PQ molecules. Notably, the designed sensor showed high selectivity and a decent linear relationship with PQ concentration in natural water samples. To the best of our knowledge, this is the first study on the preparation of Fe2O3–BCN nanosheets for PQ detection. The proposed sensor can be employed as an effective alternative tool for distinguishing and processing PQ.
Boron/nitrogen-co-doped carbon (BCN) nanosheets decorated with Fe2O3 nanocrystals (Fe2O3–BCN) were cast on a glassy carbon electrode (GCE) and applied as an electrochemical sensor to effectively detect paraquat (PQ), a toxic herbicide, in aqueous environments. A linear experiment performed using square wave voltammetry (SWV) under optimized experimental conditions produced a decent linear relationship and a low detection limit (LOD) of 2.74 nmol/L (S/N = 3). Repeatability, reproducibility, stability, and interference experiments confirmed that the Fe2O3–BCN/GCE system exhibited decent electrochemical sensing performance for PQ molecules. Notably, the designed sensor showed high selectivity and a decent linear relationship with PQ concentration in natural water samples. To the best of our knowledge, this is the first study on the preparation of Fe2O3–BCN nanosheets for PQ detection. The proposed sensor can be employed as an effective alternative tool for distinguishing and processing PQ.
2023, 34(1): 107308
doi: 10.1016/j.cclet.2022.03.031
Abstract:
Oxygen vacancy induced photothermal effect is of great significant but lack of adequate attentions for environmental remediation. In this paper, green recyclable ZnO/ZnFe2O4 with oxygen vacancy was prepared by a solvothermal-calcination method. The UV-vis light capture ability of ZnO/ZnFe2O4 microspheres is improved with the multiple light reflections due to the yolk-shell structure, and the oxygen vacancy expands the absorption range of photocatalyst and enhances photothermal conversion. The optimized photocatalyst can heat the solution from room temperature to 70 ℃ within 60 min of visible light illumination, and the light to heat conversion efficiency is achieved by 61.3%. Compared with the degradation efficiency at 20 ℃, photothermal catalysis achieves a stable degradation in 80 min, and the degradation efficiency is increased by 41.5%. This can be attributed to the fact that light induced thermal energy accelerates the migration of electrons and holes, and promotes the diffusion of free radicals by heating active centers in situ. The active species contributing to the degradation, in order of importance, are the superoxide radical, hydroxyl radical, hole and electron. The light-to-thermal assisted photocatalysis with ZnO/ZnFe2O4 provides a new sight for the pollution control in the future practical applications.
Oxygen vacancy induced photothermal effect is of great significant but lack of adequate attentions for environmental remediation. In this paper, green recyclable ZnO/ZnFe2O4 with oxygen vacancy was prepared by a solvothermal-calcination method. The UV-vis light capture ability of ZnO/ZnFe2O4 microspheres is improved with the multiple light reflections due to the yolk-shell structure, and the oxygen vacancy expands the absorption range of photocatalyst and enhances photothermal conversion. The optimized photocatalyst can heat the solution from room temperature to 70 ℃ within 60 min of visible light illumination, and the light to heat conversion efficiency is achieved by 61.3%. Compared with the degradation efficiency at 20 ℃, photothermal catalysis achieves a stable degradation in 80 min, and the degradation efficiency is increased by 41.5%. This can be attributed to the fact that light induced thermal energy accelerates the migration of electrons and holes, and promotes the diffusion of free radicals by heating active centers in situ. The active species contributing to the degradation, in order of importance, are the superoxide radical, hydroxyl radical, hole and electron. The light-to-thermal assisted photocatalysis with ZnO/ZnFe2O4 provides a new sight for the pollution control in the future practical applications.
2023, 34(1): 107322
doi: 10.1016/j.cclet.2022.03.045
Abstract:
Graphene oxide (GO) with one-atom-thick exhibit remarkable molecule sieving properties, but its low permeance flux renders it difficult to be applied in practice as a high-permeance separation membrane. In this study, we design complex membrane from covalently crosslinked GO, polydopamine (PDA), and 3-aminopropytriethoxysilane (APTES) as building blocks to fabricate the high-permeance GO-based membrane via the vacuum filtration method. A branched crosslinking product (PDA/APTES) working as a clamp grasped the hydrophilic functional groups (hydroxyl, epoxy, carboxyl) on GO for improving the GO membrane flux. The interlayer structure of the GO membrane was optimized according to the crosslinker concentration, reaction time, initial pH, and temperature for RGO/PDA/APTES (RGPA) in this study. At the optimized reaction conditions including the crosslinker concentration of 1.4 mL/L, the temperature of 80 ℃, the time of 16 h, and the initial pH of 8.5 for RGPA mixture, the interlayer gallery of RGPA membrane was effectively tunes, endowing high flux ranging from 11.98 L m−2 h−1 to 1823.97 L m−2 h−1. Besides, the RGPA membrane ensured the high rejections to dye solutions such as methylene blue (MB) (> 99%) and congo red (CR) (> 90%). Meanwhile, the superior reusable performance of the RGPA membrane was achieved, together with the rejections for MB and CR to 96.32% and 93.1% after 4 cycles, respectively. Also, the RGPA membrane possessed superior anti-fouling performances for bovine serum albumin (BSA) aqueous solution and excellent stabilities in harsh conditions (pH 3, 7 and 11). Grafting the crosslinker onto GO nanosheets exhibits the distinct advantages of achieving the high flux, high rejections to dyes, and superior reusable performance of membranes, posing a great application potential for membrane separation technology in wastewater treatment.
Graphene oxide (GO) with one-atom-thick exhibit remarkable molecule sieving properties, but its low permeance flux renders it difficult to be applied in practice as a high-permeance separation membrane. In this study, we design complex membrane from covalently crosslinked GO, polydopamine (PDA), and 3-aminopropytriethoxysilane (APTES) as building blocks to fabricate the high-permeance GO-based membrane via the vacuum filtration method. A branched crosslinking product (PDA/APTES) working as a clamp grasped the hydrophilic functional groups (hydroxyl, epoxy, carboxyl) on GO for improving the GO membrane flux. The interlayer structure of the GO membrane was optimized according to the crosslinker concentration, reaction time, initial pH, and temperature for RGO/PDA/APTES (RGPA) in this study. At the optimized reaction conditions including the crosslinker concentration of 1.4 mL/L, the temperature of 80 ℃, the time of 16 h, and the initial pH of 8.5 for RGPA mixture, the interlayer gallery of RGPA membrane was effectively tunes, endowing high flux ranging from 11.98 L m−2 h−1 to 1823.97 L m−2 h−1. Besides, the RGPA membrane ensured the high rejections to dye solutions such as methylene blue (MB) (> 99%) and congo red (CR) (> 90%). Meanwhile, the superior reusable performance of the RGPA membrane was achieved, together with the rejections for MB and CR to 96.32% and 93.1% after 4 cycles, respectively. Also, the RGPA membrane possessed superior anti-fouling performances for bovine serum albumin (BSA) aqueous solution and excellent stabilities in harsh conditions (pH 3, 7 and 11). Grafting the crosslinker onto GO nanosheets exhibits the distinct advantages of achieving the high flux, high rejections to dyes, and superior reusable performance of membranes, posing a great application potential for membrane separation technology in wastewater treatment.
2023, 34(1): 107388
doi: 10.1016/j.cclet.2022.03.111
Abstract:
For circulating tumor cells (CTCs)-based cancer diagnosis and monitoring, effective enrichment and specific analysis of CTCs present significant challenges. The biomembrane interfaces can enhance the high-affinity interactions between various receptors and ligands in life activities by mediating the rearrangement and positioning of membrane-bound components through its fluidity. Inspired by this, we have constructed a multivalent membrane nano-interface using aptamer-linked liposomes for the efficient capture of CTCs. Furthermore, the subsequent introduction of rolling circle amplification (RCA) reaction has increased the number of aptamers and extended them to the surrounding space to improve the affinity of the membrane nano-interface for CTCs. After CTCs are enriched, alkaline phosphatase overexpressed on the surface of tumor cells is used as endogenous enzyme-mediated signal amplification by catalyzing 4-nitrophenyl phosphate (pNPP) with color change, achieving the analysis of CTCs. Finally, the enrichment and visual analysis of human hepatocellular carcinoma (HepG2) with a detection limit of 10 cells/mL can be obtained by integrating the multivalent membrane nano-interface and endogenous enzyme signal amplification. The detection of the target in the serum proved this method has the potential for further clinical application and provides a potential method for studying the correlation between alkaline phosphatase dimer and cancer progression.
For circulating tumor cells (CTCs)-based cancer diagnosis and monitoring, effective enrichment and specific analysis of CTCs present significant challenges. The biomembrane interfaces can enhance the high-affinity interactions between various receptors and ligands in life activities by mediating the rearrangement and positioning of membrane-bound components through its fluidity. Inspired by this, we have constructed a multivalent membrane nano-interface using aptamer-linked liposomes for the efficient capture of CTCs. Furthermore, the subsequent introduction of rolling circle amplification (RCA) reaction has increased the number of aptamers and extended them to the surrounding space to improve the affinity of the membrane nano-interface for CTCs. After CTCs are enriched, alkaline phosphatase overexpressed on the surface of tumor cells is used as endogenous enzyme-mediated signal amplification by catalyzing 4-nitrophenyl phosphate (pNPP) with color change, achieving the analysis of CTCs. Finally, the enrichment and visual analysis of human hepatocellular carcinoma (HepG2) with a detection limit of 10 cells/mL can be obtained by integrating the multivalent membrane nano-interface and endogenous enzyme signal amplification. The detection of the target in the serum proved this method has the potential for further clinical application and provides a potential method for studying the correlation between alkaline phosphatase dimer and cancer progression.
2023, 34(1): 107391
doi: 10.1016/j.cclet.2022.03.114
Abstract:
2-Phenylethylamine (2-PEA) is one of the main ingredients for stimulants. Therefore, it is necessary to limit its use and illegal trade by conveniently detecting 2-PEA vapour. Here, a QCM based 2-PEA gas sensor was constructed by using aldehyde functionalized mesoporous carbon (FDU-15-CHO) as sensing materials designed according to Schiff base adsorption role. The 2D hexagonal mesoporous structures of the sensing material have been confirmed by small-angle X-ray diffraction (SXRD), transmission electron microscopy (TEM), and N2 adsorption-desorption isotherms. The covalent grafting of aldehyde group onto the FDU-15 was confirmed by Fourier transform infrared spectroscopy (FT-IR). FDU-15-CHO based Quartz Crystal Microbalance (QCM) sensor shows better sensitivity to 2-PEA than its parent FDU-15. Besides, the detection limit of FDU-15-CHO based sensor can reach down to 1 ppm, and its selectivity and reproducibility are satisfactory. The high concentrations of active sites in the mesopores of FDU-15 are believed to facilitate 2-PEA adsorption, and thus the presence of the -CHO group leading to sensitive and selective response, which is verified by Gaussian simulation
2-Phenylethylamine (2-PEA) is one of the main ingredients for stimulants. Therefore, it is necessary to limit its use and illegal trade by conveniently detecting 2-PEA vapour. Here, a QCM based 2-PEA gas sensor was constructed by using aldehyde functionalized mesoporous carbon (FDU-15-CHO) as sensing materials designed according to Schiff base adsorption role. The 2D hexagonal mesoporous structures of the sensing material have been confirmed by small-angle X-ray diffraction (SXRD), transmission electron microscopy (TEM), and N2 adsorption-desorption isotherms. The covalent grafting of aldehyde group onto the FDU-15 was confirmed by Fourier transform infrared spectroscopy (FT-IR). FDU-15-CHO based Quartz Crystal Microbalance (QCM) sensor shows better sensitivity to 2-PEA than its parent FDU-15. Besides, the detection limit of FDU-15-CHO based sensor can reach down to 1 ppm, and its selectivity and reproducibility are satisfactory. The high concentrations of active sites in the mesopores of FDU-15 are believed to facilitate 2-PEA adsorption, and thus the presence of the -CHO group leading to sensitive and selective response, which is verified by Gaussian simulation
2023, 34(1): 107438
doi: 10.1016/j.cclet.2022.04.036
Abstract:
Taking advantage of the Warburg effect in cancer cells, glucose conjugation has emerged as a useful strategy for targeted delivery of anticancer agents. Pristimerin is a naturally occurring triterpenoid that displays potent but non-selective cytotoxicity. We developed a convergent and modular approach to construction of glucose−payload conjugates featuring copper-mediated azide−alkyne cycloaddition and prepared a glucose conjugate of pristimerin through this approach. The anticancer activity of this conjugate was evaluated in cancer cells and normal cells; however, the selectivity toward cancer cells was not significantly improved. We then examined the extracellular stability of the conjugate and found that its ester linkage was cleaved rapidly in Dulbecco's Modified Eagle's Medium at 37 ℃, which resulted in the release of pristimerin. In fact, the inorganic components in this medium were sufficient to induce the cleavage. Given that the subtle difference between intrinsic stability and extracellular stability of the conjugate linker is often underappreciated, this work highlights the importance of the latter in the development of target-selective conjugates.
Taking advantage of the Warburg effect in cancer cells, glucose conjugation has emerged as a useful strategy for targeted delivery of anticancer agents. Pristimerin is a naturally occurring triterpenoid that displays potent but non-selective cytotoxicity. We developed a convergent and modular approach to construction of glucose−payload conjugates featuring copper-mediated azide−alkyne cycloaddition and prepared a glucose conjugate of pristimerin through this approach. The anticancer activity of this conjugate was evaluated in cancer cells and normal cells; however, the selectivity toward cancer cells was not significantly improved. We then examined the extracellular stability of the conjugate and found that its ester linkage was cleaved rapidly in Dulbecco's Modified Eagle's Medium at 37 ℃, which resulted in the release of pristimerin. In fact, the inorganic components in this medium were sufficient to induce the cleavage. Given that the subtle difference between intrinsic stability and extracellular stability of the conjugate linker is often underappreciated, this work highlights the importance of the latter in the development of target-selective conjugates.
2023, 34(1): 107446
doi: 10.1016/j.cclet.2022.04.044
Abstract:
Repeated waves of influenza virus H7N9 epidemics after 2013 have caused severe influenza in humans, with mortality reaching approximately 40%–50%. To prevent possible pandemics, the development of highly effective vaccines against influenza virus H7N9 is highly desired. In the present study, by taking advantage of the d-tetra-peptide adjuvant (GDFDFDY), we reported a simple method to prepare H7N9 vaccines. Naproxen (Npx), with good anti inflammatory and broad anti-viral effects, was employed as an N-terminal capping group to construct a hydrogel precursor, Npx-GDFDFDY. The hydrogel adjuvant was prepared using a routine heating cooling protocol and the final vaccine was ready after mixing with the split A/Zhejiang/DTID-ZJU01/2013 (H7N9) antigen by vortexing. Compared with the traditional Al(OH)3 adjuvant vaccine and the split vaccine, our hydrogel adjuvant vaccine showed the best preventive effects against H7N9 infection. A mechanistic study illustrated that higher antibody responses and variations in cytokine expression might account for its increased protective effects. Our strategy demonstrated the advantages of a peptide hydrogel adjuvant in the application of vaccines against H7N9 and demonstrated its potential application in vaccines against emerging threats from other viruses.
Repeated waves of influenza virus H7N9 epidemics after 2013 have caused severe influenza in humans, with mortality reaching approximately 40%–50%. To prevent possible pandemics, the development of highly effective vaccines against influenza virus H7N9 is highly desired. In the present study, by taking advantage of the d-tetra-peptide adjuvant (GDFDFDY), we reported a simple method to prepare H7N9 vaccines. Naproxen (Npx), with good anti inflammatory and broad anti-viral effects, was employed as an N-terminal capping group to construct a hydrogel precursor, Npx-GDFDFDY. The hydrogel adjuvant was prepared using a routine heating cooling protocol and the final vaccine was ready after mixing with the split A/Zhejiang/DTID-ZJU01/2013 (H7N9) antigen by vortexing. Compared with the traditional Al(OH)3 adjuvant vaccine and the split vaccine, our hydrogel adjuvant vaccine showed the best preventive effects against H7N9 infection. A mechanistic study illustrated that higher antibody responses and variations in cytokine expression might account for its increased protective effects. Our strategy demonstrated the advantages of a peptide hydrogel adjuvant in the application of vaccines against H7N9 and demonstrated its potential application in vaccines against emerging threats from other viruses.
2023, 34(1): 107448
doi: 10.1016/j.cclet.2022.04.046
Abstract:
MicroRNA-26a (miR-26a) has been verified to promote osteogenic differentiation of mesenchymal stem cells in recent years. The main obstacles to its application in bone regeneration are instability in the physiological environment and low efficiency of cellular membrane penetration. To overcome these problems, we constructed a novel plant virus gene delivery system based on Cowpea chlorotic mottle virus (CCMV). By encapsulating miR-26a with purified capsid protein (CP) dimers derived from CCMV, CP-miR-26a (CP26a) virus-like particles (VLPs) were obtained. CP26a retained a structure similar to the native CCMV and protected miR-26a from digestion with its exterior CP. Moreover, CP26a featured similar cellular uptake efficiency, osteogenesis promotion ability, and better biocompatibility compared with Lipofectamine2000-miR-26a (lipo26a), which indicated a promising prospect for CCMV as a novel gene delivery system.
MicroRNA-26a (miR-26a) has been verified to promote osteogenic differentiation of mesenchymal stem cells in recent years. The main obstacles to its application in bone regeneration are instability in the physiological environment and low efficiency of cellular membrane penetration. To overcome these problems, we constructed a novel plant virus gene delivery system based on Cowpea chlorotic mottle virus (CCMV). By encapsulating miR-26a with purified capsid protein (CP) dimers derived from CCMV, CP-miR-26a (CP26a) virus-like particles (VLPs) were obtained. CP26a retained a structure similar to the native CCMV and protected miR-26a from digestion with its exterior CP. Moreover, CP26a featured similar cellular uptake efficiency, osteogenesis promotion ability, and better biocompatibility compared with Lipofectamine2000-miR-26a (lipo26a), which indicated a promising prospect for CCMV as a novel gene delivery system.
2023, 34(1): 107450
doi: 10.1016/j.cclet.2022.04.048
Abstract:
The magnetism of nanographene is dominated by the structure of its carbon skeleton. However, the magnetism engineering of nanographene is hindered due to finite precursors. Here, we demonstrate an ingenious synthetic strategy to engineer the magnetism of nanographene through hetero-coupling two precursors on Au(111) surface. Bond-resolved scanning tunneling microscopy and spectroscopy results show that two homo-coupled products host a closed-shell structure, while the products with five membered ring defects perform as an open-shell one with the total spin number of 1/2, confirmed by spin-polarized density functional theory calculations. While two hetero precursors on Au(111) substrate, the hetero-coupled products both perform as the magnetic structure with total spin quantum numbers of 1/2 and 1, resulting from carbon skeleton transformations. Our work provides an effective way to engineer the magnetism of nanographene by enriching the magnetic products simultaneous, which could be extended into other controllable magnetic nanographene instruction.
The magnetism of nanographene is dominated by the structure of its carbon skeleton. However, the magnetism engineering of nanographene is hindered due to finite precursors. Here, we demonstrate an ingenious synthetic strategy to engineer the magnetism of nanographene through hetero-coupling two precursors on Au(111) surface. Bond-resolved scanning tunneling microscopy and spectroscopy results show that two homo-coupled products host a closed-shell structure, while the products with five membered ring defects perform as an open-shell one with the total spin number of 1/2, confirmed by spin-polarized density functional theory calculations. While two hetero precursors on Au(111) substrate, the hetero-coupled products both perform as the magnetic structure with total spin quantum numbers of 1/2 and 1, resulting from carbon skeleton transformations. Our work provides an effective way to engineer the magnetism of nanographene by enriching the magnetic products simultaneous, which could be extended into other controllable magnetic nanographene instruction.
2023, 34(1): 107451
doi: 10.1016/j.cclet.2022.04.049
Abstract:
The biodegradable substitution materials for bone tissue engineering have been a research hotspot. As is known to all, the biodegradability, biocompatibility, mechanical properties and plasticity of the substitution materials are the important indicators for the application of implantation materials. In this article, we reported a novel binary substitution material by blending the poly(lactic-acid)-co-(trimethylene-carbonate) and poly(glycolic-acid)-co-(trimethylene-carbonate), which are both biodegradable polymers with the same segment of flexible trimethylene-carbonate in order to accelerate the degradation rate of poly(lactic-acid)-co-(trimethylene carbonate) substrate and improve its mechanical properties. Besides, we further fabricate the porous poly(lactic-acid)-co-(trimethylene-carbonate)/poly(glycolic-acid)-co-(trimethylene-carbonate) scaffolds with uniform microstructure by the 3D extrusion printing technology in a mild printing condition. The physicochemical properties of the poly(lactic-acid)-co-(trimethylene-carbonate)/poly(glycolic-acid)-co-(trimethylene-carbonate) and the 3D printing scaffolds were investigated by universal tensile dynamometer, fourier transform infrared reflection (FTIR), scanning electron microscope (SEM) and differential scanning calorimeter (DSC). Meanwhile, the degradability of the PLLA-TMC/GA-TMC was performed in vitro degradation assays. Compared with PLLA-TMC group, PLLA-TMC/GA-TMC groups maintained the decreasing Tg, higher degradation rate and initial mechanical performance. Furthermore, the PLLA-TMC/GA-TMC 3D printing scaffolds provided shape-memory ability at 37 ℃. In summary, the PLLA-TMC/GA-TMC can be regarded as an alternative substitution material for bone tissue engineering.
The biodegradable substitution materials for bone tissue engineering have been a research hotspot. As is known to all, the biodegradability, biocompatibility, mechanical properties and plasticity of the substitution materials are the important indicators for the application of implantation materials. In this article, we reported a novel binary substitution material by blending the poly(lactic-acid)-co-(trimethylene-carbonate) and poly(glycolic-acid)-co-(trimethylene-carbonate), which are both biodegradable polymers with the same segment of flexible trimethylene-carbonate in order to accelerate the degradation rate of poly(lactic-acid)-co-(trimethylene carbonate) substrate and improve its mechanical properties. Besides, we further fabricate the porous poly(lactic-acid)-co-(trimethylene-carbonate)/poly(glycolic-acid)-co-(trimethylene-carbonate) scaffolds with uniform microstructure by the 3D extrusion printing technology in a mild printing condition. The physicochemical properties of the poly(lactic-acid)-co-(trimethylene-carbonate)/poly(glycolic-acid)-co-(trimethylene-carbonate) and the 3D printing scaffolds were investigated by universal tensile dynamometer, fourier transform infrared reflection (FTIR), scanning electron microscope (SEM) and differential scanning calorimeter (DSC). Meanwhile, the degradability of the PLLA-TMC/GA-TMC was performed in vitro degradation assays. Compared with PLLA-TMC group, PLLA-TMC/GA-TMC groups maintained the decreasing Tg, higher degradation rate and initial mechanical performance. Furthermore, the PLLA-TMC/GA-TMC 3D printing scaffolds provided shape-memory ability at 37 ℃. In summary, the PLLA-TMC/GA-TMC can be regarded as an alternative substitution material for bone tissue engineering.
2023, 34(1): 107453
doi: 10.1016/j.cclet.2022.04.051
Abstract:
Macrophages play a crucial role in initiating, maintaining, and resolving inflammation through the phenotypic shift, inducing or inhibiting the production of inflammatory cytokines. Therefore, macrophages are potential targets for treating inflammatory diseases. Andrographolide (AND) is a potent anti-inflammatory drug that can reduce pro-inflammatory cytokines and suppress NF-κB /MAPK pathway in activated macrophages. Although AND has many medicinal properties, its lower water solubility and first-pass effect in the liver have hindered its clinical application. In this context, by using a metal phenolic network as a stabilizer, we designed and prepared highly stabilized AND nanocrystals (AND-MPN Ns) with high drug loading capacity to facilitate the clinical application of AND. Our findings showed that AND-MPN Ns could be used to enhance the anti-inflammation in-vitro via macrophage polarization, reducing pro-inflammatory cytokines IL-6 and TNF-α, and suppressing the NF-κB signaling pathway activation. The results demonstrated the potential of AND-MPN Ns to combat inflammatory diseases effectively.
Macrophages play a crucial role in initiating, maintaining, and resolving inflammation through the phenotypic shift, inducing or inhibiting the production of inflammatory cytokines. Therefore, macrophages are potential targets for treating inflammatory diseases. Andrographolide (AND) is a potent anti-inflammatory drug that can reduce pro-inflammatory cytokines and suppress NF-κB /MAPK pathway in activated macrophages. Although AND has many medicinal properties, its lower water solubility and first-pass effect in the liver have hindered its clinical application. In this context, by using a metal phenolic network as a stabilizer, we designed and prepared highly stabilized AND nanocrystals (AND-MPN Ns) with high drug loading capacity to facilitate the clinical application of AND. Our findings showed that AND-MPN Ns could be used to enhance the anti-inflammation in-vitro via macrophage polarization, reducing pro-inflammatory cytokines IL-6 and TNF-α, and suppressing the NF-κB signaling pathway activation. The results demonstrated the potential of AND-MPN Ns to combat inflammatory diseases effectively.
2023, 34(1): 107460
doi: 10.1016/j.cclet.2022.04.058
Abstract:
The fluorescence lifetime of nicotinamide adenine dinucleotide (NADH), a key endogenous coenzyme and metabolic biomarker, can reflect the metabolic state of cells. To implement metabolic imaging of brain tissue at high resolution, we assembled a two-photon fluorescence lifetime imaging microscopy (FLIM) platform and verified the feasibility and stability of NADH-based two-photon FLIM in paraformaldehyde-fixed mouse cerebral slices. Furthermore, NADH based metabolic state oscillation was observed in cerebral nuclei suprachiasmatic nucleus (SCN). The free NADH fraction displayed a relatively lower level in the daytime than at the onset of night, and an ultradian oscillation at night was observed. Through the combination of high-resolution imaging and immunostaining data, the metabolic tendency of different cell types was detected after the first two hours of the day and at night. Thus, two-photon FLIM analysis of NADH in paraformaldehyde-fixed cerebral slices provides a high-resolution and label-free method to explore the metabolic state of deep brain regions.
The fluorescence lifetime of nicotinamide adenine dinucleotide (NADH), a key endogenous coenzyme and metabolic biomarker, can reflect the metabolic state of cells. To implement metabolic imaging of brain tissue at high resolution, we assembled a two-photon fluorescence lifetime imaging microscopy (FLIM) platform and verified the feasibility and stability of NADH-based two-photon FLIM in paraformaldehyde-fixed mouse cerebral slices. Furthermore, NADH based metabolic state oscillation was observed in cerebral nuclei suprachiasmatic nucleus (SCN). The free NADH fraction displayed a relatively lower level in the daytime than at the onset of night, and an ultradian oscillation at night was observed. Through the combination of high-resolution imaging and immunostaining data, the metabolic tendency of different cell types was detected after the first two hours of the day and at night. Thus, two-photon FLIM analysis of NADH in paraformaldehyde-fixed cerebral slices provides a high-resolution and label-free method to explore the metabolic state of deep brain regions.
2023, 34(1): 107463
doi: 10.1016/j.cclet.2022.04.061
Abstract:
Respiratory antibiotics have been proven clinically beneficial for the treatment of severe lung infections such as Pseudomonas aeruginosa. Maintaining a high local concentration of inhaled antibiotics for an extended time in the lung is crucial to ensure an adequate antimicrobial efficiency. In this study, we aim to investigate whether an extended exposure of ciprofloxacin (CIP), a model fluoroquinolone drug, in the lung epithelial lining fluid (ELF) could be achieved via a controlled-release formulation strategy. CIP solutions were intratracheally instilled to the rat lungs at 3 different rates, i.e., T0h (fast), T2h (medium), and T4h (slow), to mimic different release profiles of inhaled CIP formulations in the lung. Subsequently, the concentration-time profiles of CIP in the plasma and the lung ELF were obtained, respectively, to determine topical exposure index (ELF-Plasma AUC Ratio, EPR). The in silico PBPK model, validated based on the in vivo data, was used to identify the key factors that influence the disposition of CIP in the plasma and lungs. The medium and slow rates groups exhibited much higher EPR than that fast instillation group. The ELF AUC of the medium and slow instillation groups were about 200 times higher than their plasma AUC. In contrast, the ELF AUC of the fast instillation group was only about 20 times higher than the plasma AUC. The generated whole-body PBPK rat model, validated by comparison with the in vivo data, revealed that drug pulmonary absorption rate was the key factor that determined pulmonary absorption of CIP. This study suggests that controlled CIP release from inhaled formulations may extend the exposure of CIP in the ELF post pulmonary administration. It also demonstrates that combining the proposed intratracheal installation model and in silico PBPK model is a useful approach to identify the key factors that influence the absorption and disposition of inhaled medicine.
Respiratory antibiotics have been proven clinically beneficial for the treatment of severe lung infections such as Pseudomonas aeruginosa. Maintaining a high local concentration of inhaled antibiotics for an extended time in the lung is crucial to ensure an adequate antimicrobial efficiency. In this study, we aim to investigate whether an extended exposure of ciprofloxacin (CIP), a model fluoroquinolone drug, in the lung epithelial lining fluid (ELF) could be achieved via a controlled-release formulation strategy. CIP solutions were intratracheally instilled to the rat lungs at 3 different rates, i.e., T0h (fast), T2h (medium), and T4h (slow), to mimic different release profiles of inhaled CIP formulations in the lung. Subsequently, the concentration-time profiles of CIP in the plasma and the lung ELF were obtained, respectively, to determine topical exposure index (ELF-Plasma AUC Ratio, EPR). The in silico PBPK model, validated based on the in vivo data, was used to identify the key factors that influence the disposition of CIP in the plasma and lungs. The medium and slow rates groups exhibited much higher EPR than that fast instillation group. The ELF AUC of the medium and slow instillation groups were about 200 times higher than their plasma AUC. In contrast, the ELF AUC of the fast instillation group was only about 20 times higher than the plasma AUC. The generated whole-body PBPK rat model, validated by comparison with the in vivo data, revealed that drug pulmonary absorption rate was the key factor that determined pulmonary absorption of CIP. This study suggests that controlled CIP release from inhaled formulations may extend the exposure of CIP in the ELF post pulmonary administration. It also demonstrates that combining the proposed intratracheal installation model and in silico PBPK model is a useful approach to identify the key factors that influence the absorption and disposition of inhaled medicine.
2023, 34(1): 107467
doi: 10.1016/j.cclet.2022.04.065
Abstract:
The photocatalyzed synthesis of 9-arylpurines has been developed using 9H-purines and non-activated arenes. This method is highly atom economical using an acridinium photocatalyst induced by visible light under air atmosphere at room temperature. It employs no metal or external oxidant for the synthesis of 9-arylpurine derivatives.
The photocatalyzed synthesis of 9-arylpurines has been developed using 9H-purines and non-activated arenes. This method is highly atom economical using an acridinium photocatalyst induced by visible light under air atmosphere at room temperature. It employs no metal or external oxidant for the synthesis of 9-arylpurine derivatives.
2023, 34(1): 107469
doi: 10.1016/j.cclet.2022.04.067
Abstract:
Two chimeric sesterterpene synthases (AaTPS1 and AaTPS2) were functionally characterized from Alternaria alternata MB-30 isolated from the leaves of a sesterterpenoid-producing Lamiaceae plant Leucosceptrum canum. AaTPS1 generated a 5/8/6/5 tetracyclic sesteraltererol (1) and its absolute stereochemistry was determined by X-ray crystallographic analysis of its derivative 10, 11-epoxysesteraltererol (2), which enabled revision of the absolute configuration of C7 of sesterfisherol produced by NfSS and PTTS014 characterized previously and its derivative 10, 11-epoxysesterfisherol. AaTPS2 produced a 5/15 bicyclic preterpestacin I (3). Site-directed mutagenesis suggested that F192 in AaTPS1 was likely involved in controlling of the hydroxylation of C12, and eight amino acids were important for the enzyme activity of AaTPS1 and AaTPS2. The engineered Escherichia coli and Saccharomyces cerevisiae strains were constructed for the productions of compounds 1 and 3, and the highest titer of compound 1 reached 62.3 mg/L in shake-flask culture. Both compounds 1 and 2 showed anti-adipogenic activity.
Two chimeric sesterterpene synthases (AaTPS1 and AaTPS2) were functionally characterized from Alternaria alternata MB-30 isolated from the leaves of a sesterterpenoid-producing Lamiaceae plant Leucosceptrum canum. AaTPS1 generated a 5/8/6/5 tetracyclic sesteraltererol (1) and its absolute stereochemistry was determined by X-ray crystallographic analysis of its derivative 10, 11-epoxysesteraltererol (2), which enabled revision of the absolute configuration of C7 of sesterfisherol produced by NfSS and PTTS014 characterized previously and its derivative 10, 11-epoxysesterfisherol. AaTPS2 produced a 5/15 bicyclic preterpestacin I (3). Site-directed mutagenesis suggested that F192 in AaTPS1 was likely involved in controlling of the hydroxylation of C12, and eight amino acids were important for the enzyme activity of AaTPS1 and AaTPS2. The engineered Escherichia coli and Saccharomyces cerevisiae strains were constructed for the productions of compounds 1 and 3, and the highest titer of compound 1 reached 62.3 mg/L in shake-flask culture. Both compounds 1 and 2 showed anti-adipogenic activity.
2023, 34(1): 107471
doi: 10.1016/j.cclet.2022.04.069
Abstract:
An aldehyde-reactive probe based on 2-amino benzamidoxime (ABAO) framework was introduced, which can selectively label aldehydes in DNA through intramolecular ring closure under mild aqueous solutions. We screened ABAO derivatives that can undergo a cyclization with the formylated nucleobases to generate a fluorescence nucleoside, and of these derivatives 5-methoxy-ABAO (PMA) emerged as the optimal choice. PMA can sensitively and selectively react with 5fU, 5fC and AP to form fluorogenic dihydroquinazoline derivatives, which also can quantify DNA damages induced by γ-irradiation. PMA-initiated labeling strategy provides great convenience for qualitative and quantitative detection of aldehydes in DNA.
An aldehyde-reactive probe based on 2-amino benzamidoxime (ABAO) framework was introduced, which can selectively label aldehydes in DNA through intramolecular ring closure under mild aqueous solutions. We screened ABAO derivatives that can undergo a cyclization with the formylated nucleobases to generate a fluorescence nucleoside, and of these derivatives 5-methoxy-ABAO (PMA) emerged as the optimal choice. PMA can sensitively and selectively react with 5fU, 5fC and AP to form fluorogenic dihydroquinazoline derivatives, which also can quantify DNA damages induced by γ-irradiation. PMA-initiated labeling strategy provides great convenience for qualitative and quantitative detection of aldehydes in DNA.
2023, 34(1): 107473
doi: 10.1016/j.cclet.2022.04.071
Abstract:
Photoredox-catalyzed hydrodifluoromethylation of alkenes has become an effective method to introduce difluoromethyl group into organic molecules. As the reported methods involve either photocatalysts or superstoichiometric amounts of additives, we herein describe a simple alternative without using photocatalyst or additive for the hydrodifluoromethylation of alkenes, through photoactivation of difluoromethyltriphenylphosphonium iodide salt. Mechanistic studies shed light on how the transformation takes place.
Photoredox-catalyzed hydrodifluoromethylation of alkenes has become an effective method to introduce difluoromethyl group into organic molecules. As the reported methods involve either photocatalysts or superstoichiometric amounts of additives, we herein describe a simple alternative without using photocatalyst or additive for the hydrodifluoromethylation of alkenes, through photoactivation of difluoromethyltriphenylphosphonium iodide salt. Mechanistic studies shed light on how the transformation takes place.
2023, 34(1): 107476
doi: 10.1016/j.cclet.2022.04.074
Abstract:
Developing convenient, fast-response and high-performance formaldehyde detection sensor is significant but challenging. Herein, two CeO2 phases (Fm3m and P42/mnm), three facets (CeO2(100), CeO2(110) and CeO2(111)) and three adsorption sites (top, bridge and hollow) are selected as substrate to interact with formaldehyde. Twenty-eight candidated transition metals (TM) are doped on CeO2 surfaces to investigate the performance of detecting formaldehyde by density functional theory. It shows that (ⅰ) CeO2 in a cubic fluorite structure with the space group Fm3m is suitable for formaldehyde adsorption compared with P42/mnm; (ⅱ) TM-CeO2(100) (TM = Au, Hf, Nb, Ta, Zr) are considered as candidated materials to absorb formaldehyde ascribed to lower adsorption energies. The d-band center, partial density of states, charge density difference and electron localization function are employed to clarify the mechanism of TM-doped CeO2 improving the performance of formaldehyde adsorption. It obviously displays that TM doped CeO2(100) changes the d orbit and rearranges electrons resulting in the superior ability to the adsorbed formaldehyde. This work provides theoretical guidance and experimental motivation for the development of novel formaldehyde sensor based on metal oxide semiconductor materials.
Developing convenient, fast-response and high-performance formaldehyde detection sensor is significant but challenging. Herein, two CeO2 phases (Fm3m and P42/mnm), three facets (CeO2(100), CeO2(110) and CeO2(111)) and three adsorption sites (top, bridge and hollow) are selected as substrate to interact with formaldehyde. Twenty-eight candidated transition metals (TM) are doped on CeO2 surfaces to investigate the performance of detecting formaldehyde by density functional theory. It shows that (ⅰ) CeO2 in a cubic fluorite structure with the space group Fm3m is suitable for formaldehyde adsorption compared with P42/mnm; (ⅱ) TM-CeO2(100) (TM = Au, Hf, Nb, Ta, Zr) are considered as candidated materials to absorb formaldehyde ascribed to lower adsorption energies. The d-band center, partial density of states, charge density difference and electron localization function are employed to clarify the mechanism of TM-doped CeO2 improving the performance of formaldehyde adsorption. It obviously displays that TM doped CeO2(100) changes the d orbit and rearranges electrons resulting in the superior ability to the adsorbed formaldehyde. This work provides theoretical guidance and experimental motivation for the development of novel formaldehyde sensor based on metal oxide semiconductor materials.
Rapid formation of Csp3–Csp3 bonds through copper-catalyzed decarboxylative Csp3–H functionalization
2023, 34(1): 107477
doi: 10.1016/j.cclet.2022.04.075
Abstract:
Transition-metal-catalyzed decarboxylative and CH functionalization strategy for the construction of Csp2-Csp2, Csp2-Csp, and Csp2-Csp3 bonds has been extensively studied. However, research surveys of this synthetic strategy for the Csp3-Csp3 bond forming reactions are surprisingly scarce. Herein, we present an efficient approach for the rapid formation of Csp3–Csp3 bond through copper-catalyzed decarboxylative Csp3–H functionalization. The present method should provide a useful access to C3-substituted indole scaffolds with possible biological activities. Mechanistic experiments and DFT calculations supported a dual-Cu(Ⅱ)-catalytic cycle involving rate-determining decarboxylation in an outer-sphere radical pathway and spin-crossover-promoted CC bond formation. This strategy offers a promising synthesis method for the construction of Csp3–Csp3 bond in the field of synthetic and pharmaceutical chemistry and extends the number of still limited copper-catalyzed decarboxylative Csp3–Csp3 bond forming reaction.
Transition-metal-catalyzed decarboxylative and CH functionalization strategy for the construction of Csp2-Csp2, Csp2-Csp, and Csp2-Csp3 bonds has been extensively studied. However, research surveys of this synthetic strategy for the Csp3-Csp3 bond forming reactions are surprisingly scarce. Herein, we present an efficient approach for the rapid formation of Csp3–Csp3 bond through copper-catalyzed decarboxylative Csp3–H functionalization. The present method should provide a useful access to C3-substituted indole scaffolds with possible biological activities. Mechanistic experiments and DFT calculations supported a dual-Cu(Ⅱ)-catalytic cycle involving rate-determining decarboxylation in an outer-sphere radical pathway and spin-crossover-promoted CC bond formation. This strategy offers a promising synthesis method for the construction of Csp3–Csp3 bond in the field of synthetic and pharmaceutical chemistry and extends the number of still limited copper-catalyzed decarboxylative Csp3–Csp3 bond forming reaction.
Synthesis of allenyl-B(MIDA) via hydrazination/fragmentation reaction of B(MIDA)-propargylic alcohol
2023, 34(1): 107479
doi: 10.1016/j.cclet.2022.04.077
Abstract:
Allenylboronates represent a very intriguing class of organoborons but are challenging to synthesis. In addition, these compounds are typically unstable, rendering the separation difficult. We report herein a practical and concise route to a new class of stable, easy-separable allenyl B(MIDA) via a hydrazination/fragmentation of B(MIDA)-propargylic alcohols. The synthesis of optically active allenyl B(MIDA) was also achieved. Interesting reactivity of the resulting product was observed.
Allenylboronates represent a very intriguing class of organoborons but are challenging to synthesis. In addition, these compounds are typically unstable, rendering the separation difficult. We report herein a practical and concise route to a new class of stable, easy-separable allenyl B(MIDA) via a hydrazination/fragmentation of B(MIDA)-propargylic alcohols. The synthesis of optically active allenyl B(MIDA) was also achieved. Interesting reactivity of the resulting product was observed.
2023, 34(1): 107482
doi: 10.1016/j.cclet.2022.04.080
Abstract:
Stability of liposomes plays a crucial role in drug delivery, especially in oral aspect. The structural modification of liposomes has been the orientation of efforts to improve their stability and enable the controllability of payload release. This study reported a selenylation strategy to optimize the liposomal structure in an attempt to enhance the nanocarrier's stability, hence the bioavailability of emodin (EM), an active compound with poor water-solubility. EM-loaded selenized liposomes (EM-Se@LPs) were prepared by thin film dispersion followed by in situ reduction technique. The results showed that EM-Se@LPs were provided with enhancive gastrointestinal stability and exhibited sustained release of drug compared with EM-loaded liposomes (EM-LPs). However, the modified liposomes with Se depositing onto the interior and exterior bilayers did not substantially facilitate absorption of EM. The reinforced structure of liposomes irrelevant to absorption was affirmed to be due to good stability and absorbability of EM itself. Nevertheless, the present work provides an alternative option for stabilization of liposomes instead of conventional methods, which may be promising for oral delivery of physiologically unstable and/or poorly absorbed drugs and systemic drug delivery.
Stability of liposomes plays a crucial role in drug delivery, especially in oral aspect. The structural modification of liposomes has been the orientation of efforts to improve their stability and enable the controllability of payload release. This study reported a selenylation strategy to optimize the liposomal structure in an attempt to enhance the nanocarrier's stability, hence the bioavailability of emodin (EM), an active compound with poor water-solubility. EM-loaded selenized liposomes (EM-Se@LPs) were prepared by thin film dispersion followed by in situ reduction technique. The results showed that EM-Se@LPs were provided with enhancive gastrointestinal stability and exhibited sustained release of drug compared with EM-loaded liposomes (EM-LPs). However, the modified liposomes with Se depositing onto the interior and exterior bilayers did not substantially facilitate absorption of EM. The reinforced structure of liposomes irrelevant to absorption was affirmed to be due to good stability and absorbability of EM itself. Nevertheless, the present work provides an alternative option for stabilization of liposomes instead of conventional methods, which may be promising for oral delivery of physiologically unstable and/or poorly absorbed drugs and systemic drug delivery.
2023, 34(1): 107483
doi: 10.1016/j.cclet.2022.04.081
Abstract:
Plaque plays a central role in atherosclerosis (AS) progression, whereas inflammation and destruction of the plaque microenvironment contribute to plaque advancement. As a result, a therapy regime, which combines anti-inflammation and inhibition-degradation of plaque matrix, appears to be a promising strategy to combat AS. Herein, we report a pH-sensitive liposome co-loading with the anti-inflammatory agent (oridonin, ORD) and plaque-collagen protector (marimastat) for anti-AS therapy. ORD was first conjugated with hyaluronic acid (HA) to target the inflammation contributor, pro-inflammatory macrophages. Then, the conjugate assembled onto the MATT-loaded liposomes. The co-loaded system (~150 nm) significantly improved pharmacokinetics over the liposomes without anchoring the conjugate and accumulated effectively in the plaque. The preparation administration allowed efficient anti-AS activities in high-fat diet (HFD)-Apoe-/- mice by decreasing the pro-inflammatory cytokine expression in the serum, lessening the lesion area, alleviating the plaque collagen degradation, promoting macrophage polarization from phenotypic M1 to M2, reducing T helper (Th) 17 cells (Th17)/T regulatory cells (Tregs) and Th1/Th2 ratio, etc. Furthermore, the serum determination in AS patients demonstrated high expression of the inflammatory cytokines, indicating our finding may offer a potential guideline for clinical practice.
Plaque plays a central role in atherosclerosis (AS) progression, whereas inflammation and destruction of the plaque microenvironment contribute to plaque advancement. As a result, a therapy regime, which combines anti-inflammation and inhibition-degradation of plaque matrix, appears to be a promising strategy to combat AS. Herein, we report a pH-sensitive liposome co-loading with the anti-inflammatory agent (oridonin, ORD) and plaque-collagen protector (marimastat) for anti-AS therapy. ORD was first conjugated with hyaluronic acid (HA) to target the inflammation contributor, pro-inflammatory macrophages. Then, the conjugate assembled onto the MATT-loaded liposomes. The co-loaded system (~150 nm) significantly improved pharmacokinetics over the liposomes without anchoring the conjugate and accumulated effectively in the plaque. The preparation administration allowed efficient anti-AS activities in high-fat diet (HFD)-Apoe-/- mice by decreasing the pro-inflammatory cytokine expression in the serum, lessening the lesion area, alleviating the plaque collagen degradation, promoting macrophage polarization from phenotypic M1 to M2, reducing T helper (Th) 17 cells (Th17)/T regulatory cells (Tregs) and Th1/Th2 ratio, etc. Furthermore, the serum determination in AS patients demonstrated high expression of the inflammatory cytokines, indicating our finding may offer a potential guideline for clinical practice.
2023, 34(1): 107484
doi: 10.1016/j.cclet.2022.04.082
Abstract:
Pulmonary delivery is an effective drug delivery strategy for the treatment of local respiratory diseases. However, the rapid systemic absorption through the lung due to the thin barrier and persistent lung clearances influence the drug retention in the lung. In this study, we designed a lipid-coated genistein nanocrystals (Lipo-NCs) formulation to achieve enhanced efficiency of local pulmonary delivery. The Lipo-NCs were fabricated by modifying genistein nanocrystals (NCs) with phospholipid membrane through thin film hydration following the homogenization method. The prepared Lipo-NCs exhibited a decreased drug release rate compared with the naked NCs. Our results demonstrated that intracellular uptake and transcellular transport of NCs by the Calu-3 epithelial layer were reduced after lipid coating. Furthermore, the macrophages clearance was also impeded by this Lipo-NCs formulation. In vivo lung retention and distribution revealed that more genistein was retained in the lung after intratracheal administration of Lipo-NCs. The pharmacokinetic study displayed that the AUC(0-t) values of Lipo-NCs were 1.59-fold lesser than those of the NCs group, indicating a reduced systemic absorption. In conclusion, this research indicated that Lipo-NCs could be a suitable formulation for reducing systemic absorption and macrophages clearance, and thus enhancing drug concentration in lung by pulmonary delivery.
Pulmonary delivery is an effective drug delivery strategy for the treatment of local respiratory diseases. However, the rapid systemic absorption through the lung due to the thin barrier and persistent lung clearances influence the drug retention in the lung. In this study, we designed a lipid-coated genistein nanocrystals (Lipo-NCs) formulation to achieve enhanced efficiency of local pulmonary delivery. The Lipo-NCs were fabricated by modifying genistein nanocrystals (NCs) with phospholipid membrane through thin film hydration following the homogenization method. The prepared Lipo-NCs exhibited a decreased drug release rate compared with the naked NCs. Our results demonstrated that intracellular uptake and transcellular transport of NCs by the Calu-3 epithelial layer were reduced after lipid coating. Furthermore, the macrophages clearance was also impeded by this Lipo-NCs formulation. In vivo lung retention and distribution revealed that more genistein was retained in the lung after intratracheal administration of Lipo-NCs. The pharmacokinetic study displayed that the AUC(0-t) values of Lipo-NCs were 1.59-fold lesser than those of the NCs group, indicating a reduced systemic absorption. In conclusion, this research indicated that Lipo-NCs could be a suitable formulation for reducing systemic absorption and macrophages clearance, and thus enhancing drug concentration in lung by pulmonary delivery.
2023, 34(1): 107487
doi: 10.1016/j.cclet.2022.05.001
Abstract:
Reversal of regioselectivity in the catalytic asymmetric conjugate additions of 3-substituted oxindoles to β-nitroenones or β-nitroacrylates was established with chiral scandium catalysts. It enabled the construction of functionalized 3, 3-disubstituted oxindoles, including terminal and internal vinyl groups in excellent yields and ee values.
Reversal of regioselectivity in the catalytic asymmetric conjugate additions of 3-substituted oxindoles to β-nitroenones or β-nitroacrylates was established with chiral scandium catalysts. It enabled the construction of functionalized 3, 3-disubstituted oxindoles, including terminal and internal vinyl groups in excellent yields and ee values.
2023, 34(1): 107488
doi: 10.1016/j.cclet.2022.05.002
Abstract:
Polysubstituted pyrroles are very important scaffolds in many bioactive natural products and synthetic pharmaceuticals. Here, a new gold-catalyzed cycloaddition of alkynes with azadienes to access tetrasubstituted pyrroles is demonstrated. The neighboring hydroxylmethyl group serves a very important directing group through an addition/cycloaddition/elimination cascade. Diverse polysubstituted pyrroles were synthesized in good yields under mild conditions in one step, and tricyclic pyrrole containing heterocycles were easily obtained through derivatization.
Polysubstituted pyrroles are very important scaffolds in many bioactive natural products and synthetic pharmaceuticals. Here, a new gold-catalyzed cycloaddition of alkynes with azadienes to access tetrasubstituted pyrroles is demonstrated. The neighboring hydroxylmethyl group serves a very important directing group through an addition/cycloaddition/elimination cascade. Diverse polysubstituted pyrroles were synthesized in good yields under mild conditions in one step, and tricyclic pyrrole containing heterocycles were easily obtained through derivatization.
2023, 34(1): 107505
doi: 10.1016/j.cclet.2022.05.019
Abstract:
Polyaniline-supported tungsten (W@PANI) was easily prepared by immersing polyaniline (PANI) in the aqueous solution of Na2WO4. It was found to be an efficient catalyst for oxidative deoximation reaction, the very important transformation for pharmaceutical industry. Besides the green features, the method employed very few of catalytic tungsten (0.048 mol% vs. oxime substrates), resulting in the high turnover numbers (TONs) of the catalyst (ca. 103 mol/mol) and the low metal residues in product (< 0.1 ppm). The reaction is applicable for a variety of substrates, including those containing heterocycles, which are key intermediates in medicine synthesis. It has also been successfully magnified to kilogram scale production to afford the desired carbonyl products smoothly.
Polyaniline-supported tungsten (W@PANI) was easily prepared by immersing polyaniline (PANI) in the aqueous solution of Na2WO4. It was found to be an efficient catalyst for oxidative deoximation reaction, the very important transformation for pharmaceutical industry. Besides the green features, the method employed very few of catalytic tungsten (0.048 mol% vs. oxime substrates), resulting in the high turnover numbers (TONs) of the catalyst (ca. 103 mol/mol) and the low metal residues in product (< 0.1 ppm). The reaction is applicable for a variety of substrates, including those containing heterocycles, which are key intermediates in medicine synthesis. It has also been successfully magnified to kilogram scale production to afford the desired carbonyl products smoothly.
2023, 34(1): 107511
doi: 10.1016/j.cclet.2022.05.025
Abstract:
The fabrication of highly effective photosensitizers has received considerable attention because of their attractive functions and applications in the fields of photodynamic therapy, photosynthesis, photocatalysis, etc. Thus, it is highly desirable to develop a new approach to enhance photosensitization efficiency. Herein, through coordination-driven self-assembly, a series of metallacycles with efficient fluorescence resonance energy transfer (FRET) were effectively constructed, which displayed higher photosensitization efficiency and photocatalytic activity than their model metallacycles without FRET due to broadband absorption and singlet energy transfer from the energy acceptor to the energy donor. Moreover, iodization of fluorophores induced a significant enhancement of the photosensitization efficiency and photocatalytic activity of the metallacycles. This research provides an efficient strategy for improving photosensitization efficiency and a promising platform for the preparation of effective photosensitizers and photocatalysts.
The fabrication of highly effective photosensitizers has received considerable attention because of their attractive functions and applications in the fields of photodynamic therapy, photosynthesis, photocatalysis, etc. Thus, it is highly desirable to develop a new approach to enhance photosensitization efficiency. Herein, through coordination-driven self-assembly, a series of metallacycles with efficient fluorescence resonance energy transfer (FRET) were effectively constructed, which displayed higher photosensitization efficiency and photocatalytic activity than their model metallacycles without FRET due to broadband absorption and singlet energy transfer from the energy acceptor to the energy donor. Moreover, iodization of fluorophores induced a significant enhancement of the photosensitization efficiency and photocatalytic activity of the metallacycles. This research provides an efficient strategy for improving photosensitization efficiency and a promising platform for the preparation of effective photosensitizers and photocatalysts.
2023, 34(1): 107552
doi: 10.1016/j.cclet.2022.05.066
Abstract:
Although endogenous H2O2 is overexpressed in tumor tissue, the amount of endogenous H2O2 is still insufficient for chemodynamic therapy (CDT). In addition, the abundant cellular glutathione (GSH) could also consume •OH for reduced CDT. Thus, the elevation of H2O2 and the consumption of GSH in tumor tissue are essential for the increased •OH yield and amplified CDT efficacy. In this paper, host-guest interactions based supramolecular complexes self-assemblies (SCSAs) were fabricated by incorporating cinnamaldehyde (CA) and PEG-modified cyclodextrin host units (mPEG-CD-CA) with ferrocene-(phenylboronic acid pinacol ester) conjugates (Fc-BE) on the basis of CD-induced host-guest interactions. After being internalized by cancer cells, CA can be released from SCSAs through the pH-responsive acetal linkage, elevating the H2O2 level by activating NADPH oxidase. Then, Fc can catalyze the H2O2 to higher cytotoxic hydroxyl radicals (•OH). Moreover, quinone methide (QM) can be produced through H2O2-induced aryl boronic ester rearrangement and further consume the antioxidant GSH. In vitro and in vivo experiments demonstrate that SCSAs can be provided as potential amplified CDT nanoagents.
Although endogenous H2O2 is overexpressed in tumor tissue, the amount of endogenous H2O2 is still insufficient for chemodynamic therapy (CDT). In addition, the abundant cellular glutathione (GSH) could also consume •OH for reduced CDT. Thus, the elevation of H2O2 and the consumption of GSH in tumor tissue are essential for the increased •OH yield and amplified CDT efficacy. In this paper, host-guest interactions based supramolecular complexes self-assemblies (SCSAs) were fabricated by incorporating cinnamaldehyde (CA) and PEG-modified cyclodextrin host units (mPEG-CD-CA) with ferrocene-(phenylboronic acid pinacol ester) conjugates (Fc-BE) on the basis of CD-induced host-guest interactions. After being internalized by cancer cells, CA can be released from SCSAs through the pH-responsive acetal linkage, elevating the H2O2 level by activating NADPH oxidase. Then, Fc can catalyze the H2O2 to higher cytotoxic hydroxyl radicals (•OH). Moreover, quinone methide (QM) can be produced through H2O2-induced aryl boronic ester rearrangement and further consume the antioxidant GSH. In vitro and in vivo experiments demonstrate that SCSAs can be provided as potential amplified CDT nanoagents.
2023, 34(1): 107561
doi: 10.1016/j.cclet.2022.05.075
Abstract:
We found compound 12N-p-trifluoromethylbenzenesulfonyl matrinane (1) was a potent anti-diabetic agent. Thirty-five tricyclic matrinic derivatives were synthesized and determined for their stimulatory effects on glucose consumption in L6 myotubes, taking 1 as the lead. In high-fat diet (HFD) and STZ induced diabetic mice, 9a significantly lowers blood glucose, improves glucose tolerance, and especially alleviates diabetic nephropathy and islet damage. Mechanism study indicates that 9a simultaneously targets mitochondrial complex I to increase AMP/ATP ratio, as well as liver kinase B1 (LKB1) and calcium/calmodulin-dependent protein kinase (CaMKK), which synergistically activates AMPKα and then stimulates glucose transporter 4 (GLUT4) membrane translocation and 2-deoxyglucose (2-DG) uptake to exert anti-diabetic efficacy. Therefore, compound 9a with a novel structure is a promising anti-diabetic candidate with the advantage of multiple-target mechanism, worthy of further investigation.
We found compound 12N-p-trifluoromethylbenzenesulfonyl matrinane (1) was a potent anti-diabetic agent. Thirty-five tricyclic matrinic derivatives were synthesized and determined for their stimulatory effects on glucose consumption in L6 myotubes, taking 1 as the lead. In high-fat diet (HFD) and STZ induced diabetic mice, 9a significantly lowers blood glucose, improves glucose tolerance, and especially alleviates diabetic nephropathy and islet damage. Mechanism study indicates that 9a simultaneously targets mitochondrial complex I to increase AMP/ATP ratio, as well as liver kinase B1 (LKB1) and calcium/calmodulin-dependent protein kinase (CaMKK), which synergistically activates AMPKα and then stimulates glucose transporter 4 (GLUT4) membrane translocation and 2-deoxyglucose (2-DG) uptake to exert anti-diabetic efficacy. Therefore, compound 9a with a novel structure is a promising anti-diabetic candidate with the advantage of multiple-target mechanism, worthy of further investigation.
2023, 34(1): 107566
doi: 10.1016/j.cclet.2022.05.080
Abstract:
In this paper, supra-amphiphilic compounds containing disaccharides and azobenzene ends have been constructed via dynamic covalent bond. It was found that the slight structural difference of the disaccharides made significant difference in the self-assembled morphologies. Namely, three kinds of azo-disaccharide supra-amphiphiles were found to assemble into different morphologies, with the only difference in chemical structure from the disaccharides. More importantly, the structural difference between the disaccharides, including lactoside, maltoside and cellobioside was trivial. Molecular simulation revealed the packing of molecules was due to the different contribution from hydrogen bonds. The above results clearly indicated the contribution of saccharide packing, especially the related hydrogen bonding, to the final morphology of the assembled structures.
In this paper, supra-amphiphilic compounds containing disaccharides and azobenzene ends have been constructed via dynamic covalent bond. It was found that the slight structural difference of the disaccharides made significant difference in the self-assembled morphologies. Namely, three kinds of azo-disaccharide supra-amphiphiles were found to assemble into different morphologies, with the only difference in chemical structure from the disaccharides. More importantly, the structural difference between the disaccharides, including lactoside, maltoside and cellobioside was trivial. Molecular simulation revealed the packing of molecules was due to the different contribution from hydrogen bonds. The above results clearly indicated the contribution of saccharide packing, especially the related hydrogen bonding, to the final morphology of the assembled structures.
2023, 34(1): 107569
doi: 10.1016/j.cclet.2022.05.083
Abstract:
We report herein an I2/PhI(OAc)2 catalytic system for the pragmatic construction of CN bonds through CH/NH oxidative coupling protocol. Divergent pyrrolo[2, 3-b]indoles were efficiently prepared via I2-catalyzed intramolecular C–H amination reactions from (E/Z)-2-indolylenamines under metal-free conditions. Various functional groups are tolerated under mild reaction conditions and the resulting pyrrolo[2, 3-b]indoles were obtained with mostly good to excellent yields. It was interesting to observe that both the (E)- and (Z)-isomers of the starting materials were efficiently transformed into the targeted product. The I+-mediated catalytic cycle was proposed based on mechanistic studies for this reaction.
We report herein an I2/PhI(OAc)2 catalytic system for the pragmatic construction of CN bonds through CH/NH oxidative coupling protocol. Divergent pyrrolo[2, 3-b]indoles were efficiently prepared via I2-catalyzed intramolecular C–H amination reactions from (E/Z)-2-indolylenamines under metal-free conditions. Various functional groups are tolerated under mild reaction conditions and the resulting pyrrolo[2, 3-b]indoles were obtained with mostly good to excellent yields. It was interesting to observe that both the (E)- and (Z)-isomers of the starting materials were efficiently transformed into the targeted product. The I+-mediated catalytic cycle was proposed based on mechanistic studies for this reaction.
2023, 34(1): 107570
doi: 10.1016/j.cclet.2022.05.084
Abstract:
An N-heterocyclic carbene (NHC)-catalyzed carbonyl nucleophilic substitution reaction between 1-cyclopropylcarbaldehydes and N-sulfonyl imines is developed for access to linear β-aminoenone products. The β-aminoenones containing cyclopropyl fragments can be afforded in moderate to excellent yields under mild conditions. The reaction features excellent trans-diastereoselectivities and the desired aminoenone products are all afforded as Z-isomers.
An N-heterocyclic carbene (NHC)-catalyzed carbonyl nucleophilic substitution reaction between 1-cyclopropylcarbaldehydes and N-sulfonyl imines is developed for access to linear β-aminoenone products. The β-aminoenones containing cyclopropyl fragments can be afforded in moderate to excellent yields under mild conditions. The reaction features excellent trans-diastereoselectivities and the desired aminoenone products are all afforded as Z-isomers.
2023, 34(1): 107575
doi: 10.1016/j.cclet.2022.05.089
Abstract:
Gambogic acid (GA) is a potential clinical anticancer drug that can exert antitumor effects via various molecular mechanisms. Notwithstanding, GA's low water solubility, poor stability, short half-life, and unavoidable toxic side effects have significantly hampered its clinical application. Erythrocyte membrane-coated nanoparticles (RBCM-NPs) improve drug's physicochemical properties, biocompatibility, and pharmacokinetic behaviors, allowing for long-term drug circulation and passive targeting. In this study, a novel biomimetic drug delivery system (DDS) against hepatocellular carcinoma was prepared by covering RBCM on GPP-NPs (GA-loaded mPEG-PLA NPs) to develop the RBC@GPP-NPs. In comparison to RBCM-free nanoparticles and free GA, RBC@GPP-NPs improved the drug's water solubility, stability, safety, and anti-tumor activity in vivo. We expect that this bionic nanoparticle composite can expand the clinical applicability of GA and provide a feasible solution for the research and development of GA's nano-formulation.
Gambogic acid (GA) is a potential clinical anticancer drug that can exert antitumor effects via various molecular mechanisms. Notwithstanding, GA's low water solubility, poor stability, short half-life, and unavoidable toxic side effects have significantly hampered its clinical application. Erythrocyte membrane-coated nanoparticles (RBCM-NPs) improve drug's physicochemical properties, biocompatibility, and pharmacokinetic behaviors, allowing for long-term drug circulation and passive targeting. In this study, a novel biomimetic drug delivery system (DDS) against hepatocellular carcinoma was prepared by covering RBCM on GPP-NPs (GA-loaded mPEG-PLA NPs) to develop the RBC@GPP-NPs. In comparison to RBCM-free nanoparticles and free GA, RBC@GPP-NPs improved the drug's water solubility, stability, safety, and anti-tumor activity in vivo. We expect that this bionic nanoparticle composite can expand the clinical applicability of GA and provide a feasible solution for the research and development of GA's nano-formulation.
2023, 34(1): 107583
doi: 10.1016/j.cclet.2022.06.006
Abstract:
Chemotherapy is restricted by efficient drug outflow due to the multiple drug resistance (MDR) in heterogenous nature of tumor. Herein, we present a dual-responsive hyaluronic acid (HA) nanocomposite hydrogel that can not only response to the tumor microenvironment but also enhance chemotherapy. This HA hydrogel consists of a core-shell SiO2 (GOD@SiO2-Arg) and mesoporous silica nanoparticles (MSNs) with doxorubicin (DOX) as the cargo (DOX@MSN). It could rapidly release the GOD@SiO2-Arg nanoparticles at the low pH tumor-specific environment due to the cleavage of imine bond. GOD@SiO2-Arg activated by over-expressed glutathione (GSH) in tumor cells releases GOD due to the cleavage of disulfide bonds, which could oxidize glucose to produce hydrogen peroxide (H2O2) for in situ NO generation via reaction between Arg and H2O2. The validity of this study might provide a method to modulate the tumor microenvironment for enhancing chemotherapy.
Chemotherapy is restricted by efficient drug outflow due to the multiple drug resistance (MDR) in heterogenous nature of tumor. Herein, we present a dual-responsive hyaluronic acid (HA) nanocomposite hydrogel that can not only response to the tumor microenvironment but also enhance chemotherapy. This HA hydrogel consists of a core-shell SiO2 (GOD@SiO2-Arg) and mesoporous silica nanoparticles (MSNs) with doxorubicin (DOX) as the cargo (DOX@MSN). It could rapidly release the GOD@SiO2-Arg nanoparticles at the low pH tumor-specific environment due to the cleavage of imine bond. GOD@SiO2-Arg activated by over-expressed glutathione (GSH) in tumor cells releases GOD due to the cleavage of disulfide bonds, which could oxidize glucose to produce hydrogen peroxide (H2O2) for in situ NO generation via reaction between Arg and H2O2. The validity of this study might provide a method to modulate the tumor microenvironment for enhancing chemotherapy.
2023, 34(1): 107585
doi: 10.1016/j.cclet.2022.06.008
Abstract:
Inhibition of foam cell formation is considered a promising treatment method for atherosclerosis, the leading cause of cardiovascular diseases worldwide. However, currently available therapeutic strategies have shown unsatisfactory clinical outcomes. Thus, herein, we design aloperine (ALO)-loaded and hyaluronic acid (HA)-modified palladium (Pd) octahedral nanozymes (Pd@HA/ALO) that can synergistically scavenge reactive oxygen species (ROS) and downregulate cyclooxygenase-2 (COX-2) expression to induce macrophage polarization, thus inhibiting foam cell formation to attenuate atherosclerosis. Due to the targeted effect of HA on stabilin-2 and CD44, which are overexpressed in atherosclerotic plaques, Pd@HA/ALO can actively accumulate in atherosclerotic plaques. Subsequently, the antioxidative effects of Pd octahedral nanozymes are mediated by their intrinsic superoxide dismutase- and catalase-like activities capable of effective scavenging of ROS. In addition, anti-inflammatory effects are mediated by controlled, on-demand near-infrared-triggered ALO release leading to inhibition of COX-2 expression. Importantly, the combined therapy can promote the polarization of macrophages to the M2 subtype by upregulating Arg-1 and CD206 expression and downregulating expression of TNF-α, IL-1β and IL-6, thereby inhibiting atherosclerosis-related foam cell formation. In conclusion, the presented in vitro and in vivo data demonstrate that Pd@HA/ALO enhanced macrophage polarization to reduce plaque formation, identifying an attractive treatment strategy for cardiovascular disease.
Inhibition of foam cell formation is considered a promising treatment method for atherosclerosis, the leading cause of cardiovascular diseases worldwide. However, currently available therapeutic strategies have shown unsatisfactory clinical outcomes. Thus, herein, we design aloperine (ALO)-loaded and hyaluronic acid (HA)-modified palladium (Pd) octahedral nanozymes (Pd@HA/ALO) that can synergistically scavenge reactive oxygen species (ROS) and downregulate cyclooxygenase-2 (COX-2) expression to induce macrophage polarization, thus inhibiting foam cell formation to attenuate atherosclerosis. Due to the targeted effect of HA on stabilin-2 and CD44, which are overexpressed in atherosclerotic plaques, Pd@HA/ALO can actively accumulate in atherosclerotic plaques. Subsequently, the antioxidative effects of Pd octahedral nanozymes are mediated by their intrinsic superoxide dismutase- and catalase-like activities capable of effective scavenging of ROS. In addition, anti-inflammatory effects are mediated by controlled, on-demand near-infrared-triggered ALO release leading to inhibition of COX-2 expression. Importantly, the combined therapy can promote the polarization of macrophages to the M2 subtype by upregulating Arg-1 and CD206 expression and downregulating expression of TNF-α, IL-1β and IL-6, thereby inhibiting atherosclerosis-related foam cell formation. In conclusion, the presented in vitro and in vivo data demonstrate that Pd@HA/ALO enhanced macrophage polarization to reduce plaque formation, identifying an attractive treatment strategy for cardiovascular disease.
2023, 34(1): 107589
doi: 10.1016/j.cclet.2022.06.012
Abstract:
Three-residue cyclophane-forming enzymes (3-CyFEs) are a group of radical S-adenosylmethionine (SAM) enzymes involved in the biosynthesis of ribosomally synthesized and posttranslationally modified peptides (RiPPs). 3-CyFE catalyzes the crosslinking between an aromatic residue (Ω1) and a non-aromatic residue (X3) in a Ω1-X2-X3 motif to produce a cyclophane ring, a key step in the biosynthesis of the RiPP natural product triceptide. In this study, we perform a genome-wide search for the Xye-type triceptides, showing these RiPPs are likely class-specific and only present in gamma-proteobacteria. The 3-CyFE PauB from Photorhabdus australis exhibits a relaxed substrate specificity on the X3 position, but glycine in this position is not suitable for cyclophane formation. We also reconstituted the activity of PauB in vitro, showing it produces the N-terminal cyclophane firstly, and then the C-terminal ring, whereas the middle cyclophane is produced in the last step.
Three-residue cyclophane-forming enzymes (3-CyFEs) are a group of radical S-adenosylmethionine (SAM) enzymes involved in the biosynthesis of ribosomally synthesized and posttranslationally modified peptides (RiPPs). 3-CyFE catalyzes the crosslinking between an aromatic residue (Ω1) and a non-aromatic residue (X3) in a Ω1-X2-X3 motif to produce a cyclophane ring, a key step in the biosynthesis of the RiPP natural product triceptide. In this study, we perform a genome-wide search for the Xye-type triceptides, showing these RiPPs are likely class-specific and only present in gamma-proteobacteria. The 3-CyFE PauB from Photorhabdus australis exhibits a relaxed substrate specificity on the X3 position, but glycine in this position is not suitable for cyclophane formation. We also reconstituted the activity of PauB in vitro, showing it produces the N-terminal cyclophane firstly, and then the C-terminal ring, whereas the middle cyclophane is produced in the last step.
2023, 34(1): 107651
doi: 10.1016/j.cclet.2022.06.074
Abstract:
The five-year survival rate for pancreatic cancer is less than 5%. However, the current clinical multimodal therapy combined with first-line chemotherapy drugs only increases the patient's median survival from 5.0 months to 7.2 months. Consequently, a new strategy of cancer treatments is urgently needed to overcome this high-fatality disease. Through a series of biometric analyses, we found that KRAS is highly expressed in the tumor of pancreatic cancer patients, and this high expression is closely related to the poor prognosis of patients. It shows that inhibiting the expression of KRAS has great potential in gene therapy for pancreatic cancer. Given those above, we have exploited the possibility of targeted delivery of KRAS shRNA with the intelligent and bio-responsive nanomedicine to detect the special oxidative stress microenvironment of cancer cells and realize efficient cancer theranostics. Our observations demonstrate that by designing the smart self-assembled nanocapsules of melanin with fluorescent nanoclusters we can readily achieve the bio-recognition and bioimaging of cancer cells in biological solution or serum. The self-assembled nanocapsules can make a significant bio-response to the oxidative stress microenvironment of cancer cells and generate fluorescent zinc oxide Nanoclusters in situ for targeted cell bioimaging. Moreover, it can also readily facilitate cancer cell suppression through the targeted delivery of KRAS shRNA and low-temperature hyperthermia. This raises the possibility to provide a promising theranostics platform and self-assembled nanomedicine for targeted cancer diagnostics and treatments through special oxidative stress-responsive effects of cancer cells.
The five-year survival rate for pancreatic cancer is less than 5%. However, the current clinical multimodal therapy combined with first-line chemotherapy drugs only increases the patient's median survival from 5.0 months to 7.2 months. Consequently, a new strategy of cancer treatments is urgently needed to overcome this high-fatality disease. Through a series of biometric analyses, we found that KRAS is highly expressed in the tumor of pancreatic cancer patients, and this high expression is closely related to the poor prognosis of patients. It shows that inhibiting the expression of KRAS has great potential in gene therapy for pancreatic cancer. Given those above, we have exploited the possibility of targeted delivery of KRAS shRNA with the intelligent and bio-responsive nanomedicine to detect the special oxidative stress microenvironment of cancer cells and realize efficient cancer theranostics. Our observations demonstrate that by designing the smart self-assembled nanocapsules of melanin with fluorescent nanoclusters we can readily achieve the bio-recognition and bioimaging of cancer cells in biological solution or serum. The self-assembled nanocapsules can make a significant bio-response to the oxidative stress microenvironment of cancer cells and generate fluorescent zinc oxide Nanoclusters in situ for targeted cell bioimaging. Moreover, it can also readily facilitate cancer cell suppression through the targeted delivery of KRAS shRNA and low-temperature hyperthermia. This raises the possibility to provide a promising theranostics platform and self-assembled nanomedicine for targeted cancer diagnostics and treatments through special oxidative stress-responsive effects of cancer cells.
2023, 34(1): 107653
doi: 10.1016/j.cclet.2022.06.076
Abstract:
Carbon monoxide (CO) gas therapy, a novel anti-tumor technique based on the cytotoxicity from the CO released in situ, has become one of the hot topics in cancer treatment. Since the technique is oxygen-independent, it displays promising therapeutic effect for hypoxic tumor where traditional photodynamic therapy shows limited efficacy and insufficient penetration depth. To fully address these limitations of PDT, we propose a synergetic sonodynamic-CO gas releasing strategy for the therapy of hypoxic tumor. In this work, two rhenium(I) tricarbonyl complexes with different substituted ligands are investigated for US-triggered ROS generation and CO release. Our results indicated that the electron-donating NMe2-substituted complex (Re-NMe2) exhibits stronger luminescence intensity and generates more singlet oxygen (1O2) than the electron-withdrawing NO2-substituted complex (Re-NO2). In addition, Re-NMe2 displays release of CO triggered by US, thus showing high sono-cytotoxicity to tumor cells in-vitro and in-vivo. The strong ROS-generating capability combined with rapid CO-releasing feature from Re-NMe2 has made it a powerful tool for the efficient treatment of hypoxic tumor.
Carbon monoxide (CO) gas therapy, a novel anti-tumor technique based on the cytotoxicity from the CO released in situ, has become one of the hot topics in cancer treatment. Since the technique is oxygen-independent, it displays promising therapeutic effect for hypoxic tumor where traditional photodynamic therapy shows limited efficacy and insufficient penetration depth. To fully address these limitations of PDT, we propose a synergetic sonodynamic-CO gas releasing strategy for the therapy of hypoxic tumor. In this work, two rhenium(I) tricarbonyl complexes with different substituted ligands are investigated for US-triggered ROS generation and CO release. Our results indicated that the electron-donating NMe2-substituted complex (Re-NMe2) exhibits stronger luminescence intensity and generates more singlet oxygen (1O2) than the electron-withdrawing NO2-substituted complex (Re-NO2). In addition, Re-NMe2 displays release of CO triggered by US, thus showing high sono-cytotoxicity to tumor cells in-vitro and in-vivo. The strong ROS-generating capability combined with rapid CO-releasing feature from Re-NMe2 has made it a powerful tool for the efficient treatment of hypoxic tumor.
2023, 34(1): 107656
doi: 10.1016/j.cclet.2022.06.079
Abstract:
The coupling of bipolar electrode (BPE) arrays and electrofluorochromic (EFC) imaging has exhibited great abilities in bioanalysis. However, the imaging resolution and analytical performance are hampered by the large size of the electrode and the rapid diffusion of EFC molecules on the electrode surface. Here, to address the challenges, bipolar nanoelectrodes (BPnE) array and in situ immobilization strategy of EFC molecules were proposed. Anodized aluminum oxide (AAO) template-assisted Au nanoelectrodes array with high density was fabricated as BPnE array for high spatial imaging resolution. By electrically polymerizing EFC molecules on the surface of single Au nanoelectrode, the rapid diffusion of EFC molecules on the electrode surface was not only avoided, but also realizing electrofluorescent imaging on an individual nanoelectrode. Using dopamine (DA) released from living PC12 cells as a model, the proposed strategy exhibited an ultra-high sensitivity for DA analysis with a detection limit of 0.45 nmol/L and the DA release amount from a single cell was calculated to be 0.13 pmol/L. Moreover, the dynamic change of DA release under the drug stimulation from living PC12 cells could also be monitored.
The coupling of bipolar electrode (BPE) arrays and electrofluorochromic (EFC) imaging has exhibited great abilities in bioanalysis. However, the imaging resolution and analytical performance are hampered by the large size of the electrode and the rapid diffusion of EFC molecules on the electrode surface. Here, to address the challenges, bipolar nanoelectrodes (BPnE) array and in situ immobilization strategy of EFC molecules were proposed. Anodized aluminum oxide (AAO) template-assisted Au nanoelectrodes array with high density was fabricated as BPnE array for high spatial imaging resolution. By electrically polymerizing EFC molecules on the surface of single Au nanoelectrode, the rapid diffusion of EFC molecules on the electrode surface was not only avoided, but also realizing electrofluorescent imaging on an individual nanoelectrode. Using dopamine (DA) released from living PC12 cells as a model, the proposed strategy exhibited an ultra-high sensitivity for DA analysis with a detection limit of 0.45 nmol/L and the DA release amount from a single cell was calculated to be 0.13 pmol/L. Moreover, the dynamic change of DA release under the drug stimulation from living PC12 cells could also be monitored.
2023, 34(1): 107701
doi: 10.1016/j.cclet.2022.07.044
Abstract:
The SARS-CoV-2 virus is released from an infectious source (such as a sick person) and adsorbed on aerosols, which can form pathogenic microorganism aerosols, which can affect human health through airborne transmission. Efficient sampling and accurate detection of microorganisms in aerosols are the premise and basis for studying their properties and evaluating their hazard. In this study, we built a set of sub-micron aerosol detection platform, and carried out a simulation experiment on the SARS-CoV-2 aerosol in the air by wet-wall cyclone combined with immunomagnetic nanoparticle adsorption sampling and ddPCR. The feasibility of the system in aerosol detection was verified, and the influencing factors in the detection process were experimentally tested. As a result, the sampling efficiency was 29.77%, and extraction efficiency was 98.57%. The minimum detection limit per unit volume of aerosols was 250 copies (102 copies/mL, concentration factor 2.5).
The SARS-CoV-2 virus is released from an infectious source (such as a sick person) and adsorbed on aerosols, which can form pathogenic microorganism aerosols, which can affect human health through airborne transmission. Efficient sampling and accurate detection of microorganisms in aerosols are the premise and basis for studying their properties and evaluating their hazard. In this study, we built a set of sub-micron aerosol detection platform, and carried out a simulation experiment on the SARS-CoV-2 aerosol in the air by wet-wall cyclone combined with immunomagnetic nanoparticle adsorption sampling and ddPCR. The feasibility of the system in aerosol detection was verified, and the influencing factors in the detection process were experimentally tested. As a result, the sampling efficiency was 29.77%, and extraction efficiency was 98.57%. The minimum detection limit per unit volume of aerosols was 250 copies (102 copies/mL, concentration factor 2.5).
2023, 34(1): 107743
doi: 10.1016/j.cclet.2022.107743
Abstract:
Three eudesmanolide sesquiterpene-phenol hybrids, atramacronoids A−C (1−3), featuring an unusual 6/6/5/5/6 skeleton furnished by forming an unexpected C-8−C-16 linkage, were obtained from the rhizomes of Atractylodes macrocephala. Their structures and absolute configurations were elucidated by spectroscopic data analysis, chemical calculations, combined with X-ray diffractions. The plausible biosynthetic pathways for compounds 1−3 are proposed. Surprisingly, compound 1 exhibited cytotoxicity against SGC-7901 cells by inducing cells apoptosis, which might relate to the promotion of synthesis of neutrophil elastase.
Three eudesmanolide sesquiterpene-phenol hybrids, atramacronoids A−C (1−3), featuring an unusual 6/6/5/5/6 skeleton furnished by forming an unexpected C-8−C-16 linkage, were obtained from the rhizomes of Atractylodes macrocephala. Their structures and absolute configurations were elucidated by spectroscopic data analysis, chemical calculations, combined with X-ray diffractions. The plausible biosynthetic pathways for compounds 1−3 are proposed. Surprisingly, compound 1 exhibited cytotoxicity against SGC-7901 cells by inducing cells apoptosis, which might relate to the promotion of synthesis of neutrophil elastase.
2023, 34(1): 107937
doi: 10.1016/j.cclet.2022.107937
Abstract:
2023, 34(1): 107087
doi: 10.1016/j.cclet.2021.12.079
Abstract:
Separator is supposed to own outstanding thermal stability, superior wettability and electrolyte uptake, which is essential for developing high-rate and safe lithium metal batteries (LMBs). However, commercial polyolefin separators possess poor wettability and limited electrolyte uptake. For addressing this issue, we put forward a composite separator to implement above functions by doping layered-silicate (talcum) into polyvinylidene fluoride (PVDF). With significant improvement of electrolyte absorption benefiting from the strong adsorption energy values (-1.64 ~ -1.70 eV) between talcum and the electrolyte in lithium metal batteries, PVDF/Talcum (PVDF/TM) composite separator owns a small contact angle and superior electrolyte uptake. PVDF/TM composite separator with 10 wt% talcum (T-10) owns a tiny contact angle of 8°, while those of polypropylene (PP) and PVDF are 48° and 20° with commercial electrolyte. Moreover, the addition of thermotolerant talcum endows the T-10 composite separator with great thermostability, whose thermal shrinkage is only 5.39% at 150 ℃ for 0.5 h. The cell with LiFeO4 cathode and the T-10 composite separator reaches 91.7 mAh/g in discharge capacity at 4.8 mA/cm2 (10 C), far superior to that with pure PVDF separator (56.3 mAh/g) and PP (51.4 mAh/g).
Separator is supposed to own outstanding thermal stability, superior wettability and electrolyte uptake, which is essential for developing high-rate and safe lithium metal batteries (LMBs). However, commercial polyolefin separators possess poor wettability and limited electrolyte uptake. For addressing this issue, we put forward a composite separator to implement above functions by doping layered-silicate (talcum) into polyvinylidene fluoride (PVDF). With significant improvement of electrolyte absorption benefiting from the strong adsorption energy values (-1.64 ~ -1.70 eV) between talcum and the electrolyte in lithium metal batteries, PVDF/Talcum (PVDF/TM) composite separator owns a small contact angle and superior electrolyte uptake. PVDF/TM composite separator with 10 wt% talcum (T-10) owns a tiny contact angle of 8°, while those of polypropylene (PP) and PVDF are 48° and 20° with commercial electrolyte. Moreover, the addition of thermotolerant talcum endows the T-10 composite separator with great thermostability, whose thermal shrinkage is only 5.39% at 150 ℃ for 0.5 h. The cell with LiFeO4 cathode and the T-10 composite separator reaches 91.7 mAh/g in discharge capacity at 4.8 mA/cm2 (10 C), far superior to that with pure PVDF separator (56.3 mAh/g) and PP (51.4 mAh/g).
2023, 34(1): 107119
doi: 10.1016/j.cclet.2022.01.012
Abstract:
Hydrogen (H2) is considered to be a promising substitute for fossil fuels. Two-dimensional (2D) nanomaterials have exhibited an efficient electrocatalytic capacity to catalyze hydrogen evolution reaction (HER). Particularly, phase engineering of 2D nanomaterials is opening a novel research direction to endow 2D nanostructures with fascinating properties for deep applications in catalyzing HER. In this review, we briefly summarize the research progress and present the current challenges on phase engineering of 2D nanomaterials for their applications in electrocatalytic HER. Our summary will be of significance to provide fundamental understanding for designing novel 2D nanomaterials with unconventional phases to electrochemically catalyze HER.
Hydrogen (H2) is considered to be a promising substitute for fossil fuels. Two-dimensional (2D) nanomaterials have exhibited an efficient electrocatalytic capacity to catalyze hydrogen evolution reaction (HER). Particularly, phase engineering of 2D nanomaterials is opening a novel research direction to endow 2D nanostructures with fascinating properties for deep applications in catalyzing HER. In this review, we briefly summarize the research progress and present the current challenges on phase engineering of 2D nanomaterials for their applications in electrocatalytic HER. Our summary will be of significance to provide fundamental understanding for designing novel 2D nanomaterials with unconventional phases to electrochemically catalyze HER.
2023, 34(1): 107121
doi: 10.1016/j.cclet.2022.01.014
Abstract:
Lithium–sulfur (Li-S) batteries are regarded as one of the most promising energy storage devices because of their low cost, high energy density, and environmental friendliness. However, Li-S batteries suffer from sluggish reaction kinetics and serious "shuttle effect" of lithium polysulfides (LiPSs), which causes rapid decay of battery capacity and prevent their practical application. To address these problems, introducing single-atom catalysts (SACs) is an effective method to improve the electrochemical performance of Li-S batteries, due to their high catalytic efficiency and definite active sites for LiPSs. In this paper, we summarized the latest developments in enhancing the electrochemical performance of cathode for Li-S batteries through introducing different SACs. Furthermore, we briefly introduced the catalytic mechanism of SACs and discussed the strategies of synthesizing SACs, including the spatial confinement strategy and the coordination design strategy. Finally, the challenges and prospects in this field are proposed. We believe that this review would help to design and fabricate high-performance Li-S batteries via introducing SACs and boost their practical application.
Lithium–sulfur (Li-S) batteries are regarded as one of the most promising energy storage devices because of their low cost, high energy density, and environmental friendliness. However, Li-S batteries suffer from sluggish reaction kinetics and serious "shuttle effect" of lithium polysulfides (LiPSs), which causes rapid decay of battery capacity and prevent their practical application. To address these problems, introducing single-atom catalysts (SACs) is an effective method to improve the electrochemical performance of Li-S batteries, due to their high catalytic efficiency and definite active sites for LiPSs. In this paper, we summarized the latest developments in enhancing the electrochemical performance of cathode for Li-S batteries through introducing different SACs. Furthermore, we briefly introduced the catalytic mechanism of SACs and discussed the strategies of synthesizing SACs, including the spatial confinement strategy and the coordination design strategy. Finally, the challenges and prospects in this field are proposed. We believe that this review would help to design and fabricate high-performance Li-S batteries via introducing SACs and boost their practical application.
2023, 34(1): 107122
doi: 10.1016/j.cclet.2022.01.015
Abstract:
Fast-charging is considered to be a key factor in the successful expansion and use of electric vehicles. Current lithium-ion batteries (LIBs) exhibit high energy density, enabling them to be used in electric vehicles (EVs) over long distances, but they take too long to charge. In addition to modifying the electrode and battery structure, the composition of the electrolyte also affects the fast-charging capability of LIBs. This review provides a comprehensive and in-depth overview of the research progress, basic mechanism, scientific challenges and design strategies of the new fast-charging solution system, focusing on the influences that the compositions of liquid and solid electrolytes have on the fast-charging performance of LIBs. Finally, new insights, promising directions and potential solutions for the electrolytes of fast-charging systems are proposed to stimulate further research on revolutionary next-generation fast-charging LIB chemistry.
Fast-charging is considered to be a key factor in the successful expansion and use of electric vehicles. Current lithium-ion batteries (LIBs) exhibit high energy density, enabling them to be used in electric vehicles (EVs) over long distances, but they take too long to charge. In addition to modifying the electrode and battery structure, the composition of the electrolyte also affects the fast-charging capability of LIBs. This review provides a comprehensive and in-depth overview of the research progress, basic mechanism, scientific challenges and design strategies of the new fast-charging solution system, focusing on the influences that the compositions of liquid and solid electrolytes have on the fast-charging performance of LIBs. Finally, new insights, promising directions and potential solutions for the electrolytes of fast-charging systems are proposed to stimulate further research on revolutionary next-generation fast-charging LIB chemistry.
2023, 34(1): 107123
doi: 10.1016/j.cclet.2022.01.016
Abstract:
Sluggish kinetics of lithium/sulfur (Li/S) conversion chemistry and the ion channels formation in the cathode is still a bottleneck for developing future Li/S batteries with high-rate, long-cycling and high-energy. Here, a rational cathode structure design of an oxygen (O) and nitrogen (N) tailoring carbon fiber aerogel (OCNF) as a host material integrated with platinum (Pt) electrocatalysis interface is employed to regulate Li/S conversion chemistry and ion channel. The Pt nanoparticles were uniformly sprayed onto the S surface to construct the electrocatalysis interface (Pt/S/OCNF) for generating ion channels to promote the effective penetration of electrolyte into the cathode. This Pt/S/OCNF gives the cathode a high sulfur utilization of 77.5%, an excellent rate capacity of 813.2 mAh/g (2 C), and an outstanding long-cycling performance with a capacitance retention of 82.6% and a decay of 0.086% per cycle after 200 cycles at 0.5 C. Density functional theory (DFT) calculations reveal that the Pt electrocatalysis interface makes the cathode a high density of state (DOS) at Fermi level to facilitate the electrical conductivity, charge transfer kinetics and electrocatalysis to accelerate the lithium polysulfides (LiPSs) electrochemical conversion. Furthermore, the unique chemisorption structure and adsorption ability of Li2Sn (n = 1, 2, 4, 6, 8) and S8 on OCNF are attributed to the bridging effects of interfacial Pt and the bonding of N-Li. The Pt electrocatalysis interface combined with the unique 3D hierarchical porous structure and abundant functional active sites at OCNF guarantee strong adsorption confinement, fast Li/S electrocatalytic conversion and unblocked ion channels for electrolyte permeation in cathode.
Sluggish kinetics of lithium/sulfur (Li/S) conversion chemistry and the ion channels formation in the cathode is still a bottleneck for developing future Li/S batteries with high-rate, long-cycling and high-energy. Here, a rational cathode structure design of an oxygen (O) and nitrogen (N) tailoring carbon fiber aerogel (OCNF) as a host material integrated with platinum (Pt) electrocatalysis interface is employed to regulate Li/S conversion chemistry and ion channel. The Pt nanoparticles were uniformly sprayed onto the S surface to construct the electrocatalysis interface (Pt/S/OCNF) for generating ion channels to promote the effective penetration of electrolyte into the cathode. This Pt/S/OCNF gives the cathode a high sulfur utilization of 77.5%, an excellent rate capacity of 813.2 mAh/g (2 C), and an outstanding long-cycling performance with a capacitance retention of 82.6% and a decay of 0.086% per cycle after 200 cycles at 0.5 C. Density functional theory (DFT) calculations reveal that the Pt electrocatalysis interface makes the cathode a high density of state (DOS) at Fermi level to facilitate the electrical conductivity, charge transfer kinetics and electrocatalysis to accelerate the lithium polysulfides (LiPSs) electrochemical conversion. Furthermore, the unique chemisorption structure and adsorption ability of Li2Sn (n = 1, 2, 4, 6, 8) and S8 on OCNF are attributed to the bridging effects of interfacial Pt and the bonding of N-Li. The Pt electrocatalysis interface combined with the unique 3D hierarchical porous structure and abundant functional active sites at OCNF guarantee strong adsorption confinement, fast Li/S electrocatalytic conversion and unblocked ion channels for electrolyte permeation in cathode.
2023, 34(1): 107130
doi: 10.1016/j.cclet.2022.01.023
Abstract:
A lithium-sulfur (Li-S) system is an important candidate for future lithium-ion system due to its low cost and high specific theoretical capacity (1675 mAh/g, 2600 Wh/kg), which is greatly hindered by the poor conductivity of sulfur, large volume change and dissolution of lithium polysulfides. Two-dimensional (2D) materials with monolayers or few-layers usually have peculiar structures and physical/chemical properties, which can resolve the critical issues in Li-S batteries. Especially, the metal-based 2D nanomaterials, including ferrum, cobalt or other metal-based composites with various anions, can provide high conductivity, large surface area and abundant reaction sites for restraining the diffusion for lithium polysulfides. In this mini-review, we will present an overview of recent developments on metal-based 2D nanomaterials with various anions as the electrode materials for Li-S batteries. Since the main bottleneck for the Li-S system is the shuttle of polysulfides, emphasis is placed on the structure and components, physical/chemical interaction and interaction mechanisms of the 2D materials. Finally, the challenges and prospects of metal-based 2D nanomaterials for Li-S batteries are discussed and proposed.
A lithium-sulfur (Li-S) system is an important candidate for future lithium-ion system due to its low cost and high specific theoretical capacity (1675 mAh/g, 2600 Wh/kg), which is greatly hindered by the poor conductivity of sulfur, large volume change and dissolution of lithium polysulfides. Two-dimensional (2D) materials with monolayers or few-layers usually have peculiar structures and physical/chemical properties, which can resolve the critical issues in Li-S batteries. Especially, the metal-based 2D nanomaterials, including ferrum, cobalt or other metal-based composites with various anions, can provide high conductivity, large surface area and abundant reaction sites for restraining the diffusion for lithium polysulfides. In this mini-review, we will present an overview of recent developments on metal-based 2D nanomaterials with various anions as the electrode materials for Li-S batteries. Since the main bottleneck for the Li-S system is the shuttle of polysulfides, emphasis is placed on the structure and components, physical/chemical interaction and interaction mechanisms of the 2D materials. Finally, the challenges and prospects of metal-based 2D nanomaterials for Li-S batteries are discussed and proposed.
2023, 34(1): 107198
doi: 10.1016/j.cclet.2022.02.004
Abstract:
Supercapacitors (SCs) are rated as the foremost efficient devices bridging the production and consumption of renewable energy. To address the ever-increasing energy requirements, it is indispensable to further develop high-performance SCs with merits of high energy-density, acceptable price and long-term stability. This review highlights the recent advances on halogen-based functionalized chemistry engineering in the state-of-the-art electrode system for high-performance SCs, primarily referring to the doping and decoration strategies of F, Cl, Br and I elements. Due to the discrepancy of electronegativity and atomic radius, the functionalization of each halogen element endows the substrate materials with different physicochemical properties, including energy bandgap structure, porosity distribution and surface affinity. The principle of halogen embedment into host materials by precisely controlling ionic adsorption and electronic structure is presented. And, the vital perspectives on the future challenges of halogen functionalization are also discussed. This work aims to deepen the understanding of halogen-based functionalized strategies to motivate further research for the development of high-performance SCs, and it also provides a prospect for exploring new material modification methods for electrochemical energy storage.
Supercapacitors (SCs) are rated as the foremost efficient devices bridging the production and consumption of renewable energy. To address the ever-increasing energy requirements, it is indispensable to further develop high-performance SCs with merits of high energy-density, acceptable price and long-term stability. This review highlights the recent advances on halogen-based functionalized chemistry engineering in the state-of-the-art electrode system for high-performance SCs, primarily referring to the doping and decoration strategies of F, Cl, Br and I elements. Due to the discrepancy of electronegativity and atomic radius, the functionalization of each halogen element endows the substrate materials with different physicochemical properties, including energy bandgap structure, porosity distribution and surface affinity. The principle of halogen embedment into host materials by precisely controlling ionic adsorption and electronic structure is presented. And, the vital perspectives on the future challenges of halogen functionalization are also discussed. This work aims to deepen the understanding of halogen-based functionalized strategies to motivate further research for the development of high-performance SCs, and it also provides a prospect for exploring new material modification methods for electrochemical energy storage.
2023, 34(1): 107202
doi: 10.1016/j.cclet.2022.02.008
Abstract:
A new biobased flame retardant (MHPA) with remarkable compatibility was synthesized via a facile and low-cost neutralization reaction of magnesium hydroxide (MH) and phytic acid (PA). By blending the prepared MHPA into ethylene vinyl acetate (EVA), the fire retardancy, smoke suppression and mechanical properties of the composites were significantly improved. When 50 wt% of MH was added into EVA matrix, the value of limiting oxygen index (LOI) reached 26.1%. Whereas, when 10 wt% MH in the EVA composites (with initial 50 wt% MH) was replaced by MHPA, the resulted EVA composites had a LOI value of 30.8%, indicating high efficiency of addition of MHPA to improve flame retardancy. Moreover, the heat release rate (HRR) and total smoke production (TSP) of the EVA composites reduced by 54.4% and 27.6%, respectively, suggesting that incorporation of MHPA could effectively hinder rapid degradation of EVA composites during burning process. The fire-retardant mechanism may reside in that the MHPA combined with MH can present the excellent carbonization and expansion effects. This study illustrates that the biobased MHPA has a broad application prospect to develop flame-retardant EVA composites.
A new biobased flame retardant (MHPA) with remarkable compatibility was synthesized via a facile and low-cost neutralization reaction of magnesium hydroxide (MH) and phytic acid (PA). By blending the prepared MHPA into ethylene vinyl acetate (EVA), the fire retardancy, smoke suppression and mechanical properties of the composites were significantly improved. When 50 wt% of MH was added into EVA matrix, the value of limiting oxygen index (LOI) reached 26.1%. Whereas, when 10 wt% MH in the EVA composites (with initial 50 wt% MH) was replaced by MHPA, the resulted EVA composites had a LOI value of 30.8%, indicating high efficiency of addition of MHPA to improve flame retardancy. Moreover, the heat release rate (HRR) and total smoke production (TSP) of the EVA composites reduced by 54.4% and 27.6%, respectively, suggesting that incorporation of MHPA could effectively hinder rapid degradation of EVA composites during burning process. The fire-retardant mechanism may reside in that the MHPA combined with MH can present the excellent carbonization and expansion effects. This study illustrates that the biobased MHPA has a broad application prospect to develop flame-retardant EVA composites.
2023, 34(1): 107254
doi: 10.1016/j.cclet.2022.02.059
Abstract:
Analytical chemistry plays an important role in the qualitive and quantitative analysis for molecules in the various circumstances, especially for the high-resolution analysis. The dual-comb spectroscopy (DCS) technology with the characteristics of high resolution, high sensitivity and instantaneous sampling exhibited a great potential in high-resolution in-situ spectral methods and has been active in the fields of spatial ranging, air composition analysis, reaction monitoring and so on. In this review, we will summarize the principle of DCS according to the different wavelength coverage and overview the applications of DCS in analytical chemistry.
Analytical chemistry plays an important role in the qualitive and quantitative analysis for molecules in the various circumstances, especially for the high-resolution analysis. The dual-comb spectroscopy (DCS) technology with the characteristics of high resolution, high sensitivity and instantaneous sampling exhibited a great potential in high-resolution in-situ spectral methods and has been active in the fields of spatial ranging, air composition analysis, reaction monitoring and so on. In this review, we will summarize the principle of DCS according to the different wavelength coverage and overview the applications of DCS in analytical chemistry.
2023, 34(1): 107275
doi: 10.1016/j.cclet.2022.02.080
Abstract:
Heterogeneous catalysis is a vivid branch of traditional catalysis field, with the advantage of high efficiency and being easily separated from reactants and products after reaction, and have received widespread attentions in large-scale industrial production, especially in the field of energy utilization. Boron has been found to be a key functional component for designing high-performance heterogeneous catalysts. In this review, we cover and categorize the past and recent progress in boron-containing materials and their applications in heterogeneous catalysis particularly in energy‐related fields. The fundamental roles of boron components in the emerging heterogeneous catalysis of construction, regulation and stabilization of active phases/sites are highlighted, with the emphasis on how they regulating structural and electronic properties of host materials. We then categorize boron-containing catalysts into six kinds mainly including intermetallic boride catalysts, metal boride-derived catalysts, boron-doped catalysts, metal boride-decorated catalysts, boron-containing compounds as catalyst supports, and single-boron-site catalysts, as well as try to establish structure-catalytic activity relationship. The catalytic applications of these six boron-containing catalysts are discussed separately, focusing on the energy-related reactions such as hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), carbon dioxide reduction reaction (CO2RR) and nitrogen reduction reaction (NRR). Finally, the opportunities and challenges related to boron-containing compounds in the field of catalysis are prospected.
Heterogeneous catalysis is a vivid branch of traditional catalysis field, with the advantage of high efficiency and being easily separated from reactants and products after reaction, and have received widespread attentions in large-scale industrial production, especially in the field of energy utilization. Boron has been found to be a key functional component for designing high-performance heterogeneous catalysts. In this review, we cover and categorize the past and recent progress in boron-containing materials and their applications in heterogeneous catalysis particularly in energy‐related fields. The fundamental roles of boron components in the emerging heterogeneous catalysis of construction, regulation and stabilization of active phases/sites are highlighted, with the emphasis on how they regulating structural and electronic properties of host materials. We then categorize boron-containing catalysts into six kinds mainly including intermetallic boride catalysts, metal boride-derived catalysts, boron-doped catalysts, metal boride-decorated catalysts, boron-containing compounds as catalyst supports, and single-boron-site catalysts, as well as try to establish structure-catalytic activity relationship. The catalytic applications of these six boron-containing catalysts are discussed separately, focusing on the energy-related reactions such as hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), carbon dioxide reduction reaction (CO2RR) and nitrogen reduction reaction (NRR). Finally, the opportunities and challenges related to boron-containing compounds in the field of catalysis are prospected.
2023, 34(1): 107389
doi: 10.1016/j.cclet.2022.03.112
Abstract:
Heteroatom doped porous carbon materials have emerged as essential cathode material for metal-air battery systems in the context of soaring demands for clean energy conversion and storage. Herein, a three-dimensional nitrogen-doped carbon self-supported electrode (TNCSE) is fabricated through thermal treatment and acid activation of raw wood. The resulting TNCSE retains the hierarchical porous architecture of parent raw lumber and holds substantial defect sites and doped N sites in the carbon skeleton. Assembled as a cathode in the rechargeable zinc-air battery, the TNCSE exhibits a superior peak power density of 134.02 mW/cm2 and an energy density of 835.92 mAh/g, significantly exceeding the ones reference commercial 20% Pt/C does. More strikingly, a limited performance decay of 1.47% after an ultra long-period (500 h) cycle is also achieved on the TNCSE. This work could offer a green and cost-save approach for rationally converting biomass into a robust self-supporting cathode material for a rechargeable zinc-air battery.
Heteroatom doped porous carbon materials have emerged as essential cathode material for metal-air battery systems in the context of soaring demands for clean energy conversion and storage. Herein, a three-dimensional nitrogen-doped carbon self-supported electrode (TNCSE) is fabricated through thermal treatment and acid activation of raw wood. The resulting TNCSE retains the hierarchical porous architecture of parent raw lumber and holds substantial defect sites and doped N sites in the carbon skeleton. Assembled as a cathode in the rechargeable zinc-air battery, the TNCSE exhibits a superior peak power density of 134.02 mW/cm2 and an energy density of 835.92 mAh/g, significantly exceeding the ones reference commercial 20% Pt/C does. More strikingly, a limited performance decay of 1.47% after an ultra long-period (500 h) cycle is also achieved on the TNCSE. This work could offer a green and cost-save approach for rationally converting biomass into a robust self-supporting cathode material for a rechargeable zinc-air battery.
2023, 34(1): 107443
doi: 10.1016/j.cclet.2022.04.041
Abstract:
Due to the abundant sodium reserves and high safety, sodium ion batteries (SIBs) are foreseen a promising future. While, hard carbon materials are very suitable for the anode of SIBs owing to their structure and cost advantages. However, the unsatisfactory initial coulombic efficiency (ICE) is one of the crucial blemishes of hard carbon materials and the slow sodium storage kinetics also hinders their wide application. Herein, with spherical nano SiO2 as pore-forming agent, gelatin and polytetrafluoroethylene as carbon sources, a multi-porous carbon (MPC) material can be easily obtained via a co-pyrolysis method, by which carbonization and template removal can be achieved synchronously without the assistance of strong acids or strong bases. As a result, the MPC anode exhibited remarkable ICE of 83% and a high rate capability (208 mAh/g at 5 A/g) when used in sodium-ion half cells. Additionally, coupling with Na3V2(PO4)3 as the cathode to assemble full cells, the as-fabricated MPC//NVP full cell delivered a good rate capability (146 mAh/g at 5 A/g) as well, implying a good application prospect the MPC anode has
Due to the abundant sodium reserves and high safety, sodium ion batteries (SIBs) are foreseen a promising future. While, hard carbon materials are very suitable for the anode of SIBs owing to their structure and cost advantages. However, the unsatisfactory initial coulombic efficiency (ICE) is one of the crucial blemishes of hard carbon materials and the slow sodium storage kinetics also hinders their wide application. Herein, with spherical nano SiO2 as pore-forming agent, gelatin and polytetrafluoroethylene as carbon sources, a multi-porous carbon (MPC) material can be easily obtained via a co-pyrolysis method, by which carbonization and template removal can be achieved synchronously without the assistance of strong acids or strong bases. As a result, the MPC anode exhibited remarkable ICE of 83% and a high rate capability (208 mAh/g at 5 A/g) when used in sodium-ion half cells. Additionally, coupling with Na3V2(PO4)3 as the cathode to assemble full cells, the as-fabricated MPC//NVP full cell delivered a good rate capability (146 mAh/g at 5 A/g) as well, implying a good application prospect the MPC anode has
2023, 34(1): 107461
doi: 10.1016/j.cclet.2022.04.059
Abstract:
Oral and maxillofacial diseases are a group of high-incidence disorders that affect people's life quality to a great extent, while the wet and highly movable environment of the related regions brings challenges to traditional therapies. Faced with the obstacles of insufficient adhesive strength and ensuing short drug retention time, conventional oral therapeutic agents often have difficulty in achieving their desired efficacy. Oral and maxillofacial wet-adhesive materials have the advantages of excellent wet environment retention, internal stability, plasticity, and clinical potential, thus have become a significant research direction in the field of oral related disorders healing. In the past decade, the development of oral adhesive materials with good wet adhesion has accelerated based on the chemical molecular interaction, physical interlocking, and biological adhesion mechanisms, including biomimetic-inspired materials, naturally derived polymer–based materials and adhesive electrospun fiber films. These fancy wet-adhesive materials can be used for oral mucosal drug delivery, oral vaccination, wound healing, and bone defects treatments. Despite their numerous novel applications, wet-adhesive materials in stomatology still face unresolved challenges from material and biological aspects. Here, advances in designs of oral and maxillofacial wet-adhesive materials are reviewed in terms of design backgrounds, attachment mechanisms, and common classifications. Recent demonstrations of wet-adhesive materials for oral and maxillofacial region medical applications from drug delivery to multifunctional tissue treatments are presented. To conclude, current challenges and prospects on potential applications of oral and maxillofacial wet-adhesive materials are also briefly discussed.
Oral and maxillofacial diseases are a group of high-incidence disorders that affect people's life quality to a great extent, while the wet and highly movable environment of the related regions brings challenges to traditional therapies. Faced with the obstacles of insufficient adhesive strength and ensuing short drug retention time, conventional oral therapeutic agents often have difficulty in achieving their desired efficacy. Oral and maxillofacial wet-adhesive materials have the advantages of excellent wet environment retention, internal stability, plasticity, and clinical potential, thus have become a significant research direction in the field of oral related disorders healing. In the past decade, the development of oral adhesive materials with good wet adhesion has accelerated based on the chemical molecular interaction, physical interlocking, and biological adhesion mechanisms, including biomimetic-inspired materials, naturally derived polymer–based materials and adhesive electrospun fiber films. These fancy wet-adhesive materials can be used for oral mucosal drug delivery, oral vaccination, wound healing, and bone defects treatments. Despite their numerous novel applications, wet-adhesive materials in stomatology still face unresolved challenges from material and biological aspects. Here, advances in designs of oral and maxillofacial wet-adhesive materials are reviewed in terms of design backgrounds, attachment mechanisms, and common classifications. Recent demonstrations of wet-adhesive materials for oral and maxillofacial region medical applications from drug delivery to multifunctional tissue treatments are presented. To conclude, current challenges and prospects on potential applications of oral and maxillofacial wet-adhesive materials are also briefly discussed.
2023, 34(1): 107474
doi: 10.1016/j.cclet.2022.04.072
Abstract:
Silkworm pupa protein (SPP) that obtained by traditional method usually had a high fat content, which would impose restrictions on the further use of SPP. Herein, various functionalized ionic liquids (ILs) were used to extract SPP from silkworm pupae, the structure-performance relationship of ILs with their SPP separation performance were explored at the same time. The research showed that the maximum extraction yield of SPP was up to 62.6% with less than 0.5% low fat content by using 1-ethyl-3-methylimidazolium chloride ([Emim]Cl), when the dissolution experiment was conducted at 90 ℃ for 24 h with ethanol bath as the regeneration solvent. Comparing with the structure of raw material, the regenerated SPP maintained the native protein backbone. Meanwhile, all regenerated SPP showed a decreased crystallinity, which also exhibited decreased fraction of the α-helix comparing to that β-sheet united with coil random structures.
Silkworm pupa protein (SPP) that obtained by traditional method usually had a high fat content, which would impose restrictions on the further use of SPP. Herein, various functionalized ionic liquids (ILs) were used to extract SPP from silkworm pupae, the structure-performance relationship of ILs with their SPP separation performance were explored at the same time. The research showed that the maximum extraction yield of SPP was up to 62.6% with less than 0.5% low fat content by using 1-ethyl-3-methylimidazolium chloride ([Emim]Cl), when the dissolution experiment was conducted at 90 ℃ for 24 h with ethanol bath as the regeneration solvent. Comparing with the structure of raw material, the regenerated SPP maintained the native protein backbone. Meanwhile, all regenerated SPP showed a decreased crystallinity, which also exhibited decreased fraction of the α-helix comparing to that β-sheet united with coil random structures.
2023, 34(1): 107501
doi: 10.1016/j.cclet.2022.05.015
Abstract:
Lithium-sulfur (Li-S) battery has been considered as one of the most promising next generation energy storage technologies for its overwhelming merits of high theoretical specific capacity (1673 mAh/g), high energy density (2500 Wh/kg), low cost, and environmentally friendliness of sulfur. However, critical drawbacks, including inherent low conductivity of sulfur and Li2S, large volume changes of sulfur cathodes, undesirable shuttling and sluggish redox kinetics of polysulfides, seriously deteriorate the energy density, cycle life and rate capability of Li-S battery, and thus limit its practical applications. Herein, we reviewed the recent developments addressing these problems through iron-based nanomaterials for effective synergistic immobilization as well as conversion reaction kinetics acceleration for polysulfides. The mechanist configurations between different iron-based nanomaterials and polysulfides for entrapment and conversion acceleration were summarized at first. Then we concluded the recent progresses on utilizing various iron-based nanomaterials in Li-S battery as sulfur hosts, separators and cathode interlayers. Finally, we discussed the challenges and perspectives for designing high sulfur loading cathode architectures along with outstanding chemisorption capability and catalytic activity.
Lithium-sulfur (Li-S) battery has been considered as one of the most promising next generation energy storage technologies for its overwhelming merits of high theoretical specific capacity (1673 mAh/g), high energy density (2500 Wh/kg), low cost, and environmentally friendliness of sulfur. However, critical drawbacks, including inherent low conductivity of sulfur and Li2S, large volume changes of sulfur cathodes, undesirable shuttling and sluggish redox kinetics of polysulfides, seriously deteriorate the energy density, cycle life and rate capability of Li-S battery, and thus limit its practical applications. Herein, we reviewed the recent developments addressing these problems through iron-based nanomaterials for effective synergistic immobilization as well as conversion reaction kinetics acceleration for polysulfides. The mechanist configurations between different iron-based nanomaterials and polysulfides for entrapment and conversion acceleration were summarized at first. Then we concluded the recent progresses on utilizing various iron-based nanomaterials in Li-S battery as sulfur hosts, separators and cathode interlayers. Finally, we discussed the challenges and perspectives for designing high sulfur loading cathode architectures along with outstanding chemisorption capability and catalytic activity.
2023, 34(1): 107565
doi: 10.1016/j.cclet.2022.05.079
Abstract:
O-Acyl ketoximes has been proven to be versatile building blocks for practical construction of N-heterocycles. In the last few years, diverse catalytic systems have been discovered to enable efficient transformations of O-acyl ketoximes to a range of nitrogen-heterocycles. Herein, we summarized our recent examples of novel nitrogen-heterocycle formation with new function findings of O-acyl ketoximes through facile aerobic copper catalysis, metal-free NO bond activation, multi-component assembly, and bis-annulations. From the green chemistry perspective, these works represent efficient methods with high atom economy, high selectivity, and minimized chemical waste. These findings also complement well to the previous mainly copper-based catalytic systems and more importantly enrich the oxime chemistry in organic synthesis.
O-Acyl ketoximes has been proven to be versatile building blocks for practical construction of N-heterocycles. In the last few years, diverse catalytic systems have been discovered to enable efficient transformations of O-acyl ketoximes to a range of nitrogen-heterocycles. Herein, we summarized our recent examples of novel nitrogen-heterocycle formation with new function findings of O-acyl ketoximes through facile aerobic copper catalysis, metal-free NO bond activation, multi-component assembly, and bis-annulations. From the green chemistry perspective, these works represent efficient methods with high atom economy, high selectivity, and minimized chemical waste. These findings also complement well to the previous mainly copper-based catalytic systems and more importantly enrich the oxime chemistry in organic synthesis.
2023, 34(1): 107578
doi: 10.1016/j.cclet.2022.06.001
Abstract:
Nine new fluorine-containing drugs have been approved by the US Food and Drug Administration (FDA) in 2021, which are presented in this review article. These small molecular drugs feature aromatic fluorine, trifluoromethyl and chlorodifluoro groups. The therapeutic areas of these fluorine-containing drugs include multiple myeloma, lymphoma, HIV, chronic heart failure, chronic myeloid leukemia, (ANCA)-associated vasculitis, migraines, von Hippel-Lindau disease, and non-small cell lung cancer. The brief biological activities and the synthetic methods have been discussed in this review for each of these nine drugs.
Nine new fluorine-containing drugs have been approved by the US Food and Drug Administration (FDA) in 2021, which are presented in this review article. These small molecular drugs feature aromatic fluorine, trifluoromethyl and chlorodifluoro groups. The therapeutic areas of these fluorine-containing drugs include multiple myeloma, lymphoma, HIV, chronic heart failure, chronic myeloid leukemia, (ANCA)-associated vasculitis, migraines, von Hippel-Lindau disease, and non-small cell lung cancer. The brief biological activities and the synthetic methods have been discussed in this review for each of these nine drugs.
2023, 34(1): 107196
doi: 10.1016/j.cclet.2022.02.002
Abstract:
The cycloaddition reactions of methane and ethylene mediated by Ir+ have been designed and studied by the techniques of mass spectrometry in conjunction with theoretical calculations. Studies have shown that Ir+ can mediate the cycloaddition reaction of CH4 and two C2H4 to generate a half-sandwich structure IrHCp+ (Cp = η5-C5H5) including pentamethylcyclopentadienyl ligand by continuous dehydrogenation reaction with the forming of three C-C bonds and seven C-H bonds. The orbital analysis indicates the mechanism of the cyclization reaction to generation of pentamethylcyclopentadienyl ligand with odd number carbon atom depends on the overlap of π orbitals in -C2H2 and carbene, which is more difficult than the forming of cyclobutadiene ligand and benzene. This study may help to understand the reaction mechanism in the cycloaddition reactions of organic compounds, which will be useful to guide the rational design of new catalysts with tailored selectivity and increased efficiency.
The cycloaddition reactions of methane and ethylene mediated by Ir+ have been designed and studied by the techniques of mass spectrometry in conjunction with theoretical calculations. Studies have shown that Ir+ can mediate the cycloaddition reaction of CH4 and two C2H4 to generate a half-sandwich structure IrHCp+ (Cp = η5-C5H5) including pentamethylcyclopentadienyl ligand by continuous dehydrogenation reaction with the forming of three C-C bonds and seven C-H bonds. The orbital analysis indicates the mechanism of the cyclization reaction to generation of pentamethylcyclopentadienyl ligand with odd number carbon atom depends on the overlap of π orbitals in -C2H2 and carbene, which is more difficult than the forming of cyclobutadiene ligand and benzene. This study may help to understand the reaction mechanism in the cycloaddition reactions of organic compounds, which will be useful to guide the rational design of new catalysts with tailored selectivity and increased efficiency.
2023, 34(1): 107209
doi: 10.1016/j.cclet.2022.02.015
Abstract:
We present the synthesis, characterization and photoluminescence properties of uranium-containing selenotungstate, [(UO2)3(SeO3)3Na5(H2O)6(SeW6O21)(SeW9O33)3]21–, which was isolated by a one-pot reaction of uranium nitrate with sodium tungstate and sodium selenite in a pH 5.2 aqueous solution at 90 ℃. In this study, the effect of the introduction of lone-electron pair containing heteroatoms on the structure is demonstrated, a three-layered heterometallic {Se3U3Na5} cluster is encapsulated by two different anionic building block units: three trivacant Keggin {B-α-SeW9O33} and one Anderson {SeW6O21}. To our knowledge, the {Se3U3Na5} cluster has never been observed in the polyoxometalate chemistry. The solid-state photoluminescence properties and lifetime decay behaviours of the title compound (1) have been measured at room temperature, and the photoluminescence spectrum displays the characteristic emission bands of corresponding uranyl cations. In addition, the photoluminescence quantum yield of 1 is 72%, which is almost three times that of starting material UO2(NO3)2·6H2O (27%). By using this strategy, we envision that an increasing number of assemblies with 'open' clusters may be designed and obtained, in which the exposed oxygen atoms show strong affinity towards metal ions, providing new opportunities to generate bigger clusters or to tune existing properties.
We present the synthesis, characterization and photoluminescence properties of uranium-containing selenotungstate, [(UO2)3(SeO3)3Na5(H2O)6(SeW6O21)(SeW9O33)3]21–, which was isolated by a one-pot reaction of uranium nitrate with sodium tungstate and sodium selenite in a pH 5.2 aqueous solution at 90 ℃. In this study, the effect of the introduction of lone-electron pair containing heteroatoms on the structure is demonstrated, a three-layered heterometallic {Se3U3Na5} cluster is encapsulated by two different anionic building block units: three trivacant Keggin {B-α-SeW9O33} and one Anderson {SeW6O21}. To our knowledge, the {Se3U3Na5} cluster has never been observed in the polyoxometalate chemistry. The solid-state photoluminescence properties and lifetime decay behaviours of the title compound (1) have been measured at room temperature, and the photoluminescence spectrum displays the characteristic emission bands of corresponding uranyl cations. In addition, the photoluminescence quantum yield of 1 is 72%, which is almost three times that of starting material UO2(NO3)2·6H2O (27%). By using this strategy, we envision that an increasing number of assemblies with 'open' clusters may be designed and obtained, in which the exposed oxygen atoms show strong affinity towards metal ions, providing new opportunities to generate bigger clusters or to tune existing properties.
2023, 34(1): 107222
doi: 10.1016/j.cclet.2022.02.027
Abstract:
Low-cost and efficient oxygen reduction reaction (ORR) electrocatalysts are the key to developing Zn-air batteries for renewable energy storage. Herein, the Mn-N-P doped carbon sphere was prepared through polymerization of hexachlorotripolyphosphazene (HCCP) and phloroglucinol, and then followed the calcination at 900 ℃. Theory calculations demonstrated the introduction of Mn in N-P doped carbon could lower the dissociation barrier of O2 into O* and promote the ORR through a 4e− pathway. The as-prepared catalysts exhibited a half-wave potential of 0.82 V vs. RHE and limiting current density of 5.2 mA/cm2 toward ORR, which was comparable to those of the commercial Pt/C catalysts. In addition, Zn-air batteries with 0.05 Mn-N-P-C catalysts showed a high specific capacity of 830 mAh/gZn and excellent cycle stability. This facile approach demonstrated herein could be a solution to develop optimum non-precious metal catalysts for the application in cathodes of proton exchange membrane fuel cells. This study also provides new insight to design the catalysts of multi-heteroatom coordinated metal in the carbon matrix for both fundamental researches and practical applications.
Low-cost and efficient oxygen reduction reaction (ORR) electrocatalysts are the key to developing Zn-air batteries for renewable energy storage. Herein, the Mn-N-P doped carbon sphere was prepared through polymerization of hexachlorotripolyphosphazene (HCCP) and phloroglucinol, and then followed the calcination at 900 ℃. Theory calculations demonstrated the introduction of Mn in N-P doped carbon could lower the dissociation barrier of O2 into O* and promote the ORR through a 4e− pathway. The as-prepared catalysts exhibited a half-wave potential of 0.82 V vs. RHE and limiting current density of 5.2 mA/cm2 toward ORR, which was comparable to those of the commercial Pt/C catalysts. In addition, Zn-air batteries with 0.05 Mn-N-P-C catalysts showed a high specific capacity of 830 mAh/gZn and excellent cycle stability. This facile approach demonstrated herein could be a solution to develop optimum non-precious metal catalysts for the application in cathodes of proton exchange membrane fuel cells. This study also provides new insight to design the catalysts of multi-heteroatom coordinated metal in the carbon matrix for both fundamental researches and practical applications.
2023, 34(1): 107480
doi: 10.1016/j.cclet.2022.04.078
Abstract:
Organic semiconductors are promising candidates as photoactive layers for photoelectrodes used in photoelectrochemical (PEC) cells due to their excellent light absorption and efficient charge transport properties with the help of interfacial materials. However, the use of multilayers will make the charge transfer mechanism more complicated and decrease the PEC performance of the photoelectrode caused by the increased contact resistance. In this work, a PM6:Y6 bulk heterojunction (BHJ)-based photocathode is fabricated for efficient PEC hydrogen evolution reaction (HER) in an acidic aqueous solution. With RuO2 as an interfacial modification layer, the photocathode with a simple structure (fluorine-doped tin oxide (FTO)/PM6:Y6/RuO2) generates a maximum photocurrent density up to −15 mA/cm2 at 0 V vs. reference hydrogen electrode (RHE), outperforming all previously reported BHJ-based photocathodes in terms of PEC performance. The highest ratiometric power-saved efficiency of 3.7% is achieved at 0.4 V vs. RHE.
Organic semiconductors are promising candidates as photoactive layers for photoelectrodes used in photoelectrochemical (PEC) cells due to their excellent light absorption and efficient charge transport properties with the help of interfacial materials. However, the use of multilayers will make the charge transfer mechanism more complicated and decrease the PEC performance of the photoelectrode caused by the increased contact resistance. In this work, a PM6:Y6 bulk heterojunction (BHJ)-based photocathode is fabricated for efficient PEC hydrogen evolution reaction (HER) in an acidic aqueous solution. With RuO2 as an interfacial modification layer, the photocathode with a simple structure (fluorine-doped tin oxide (FTO)/PM6:Y6/RuO2) generates a maximum photocurrent density up to −15 mA/cm2 at 0 V vs. reference hydrogen electrode (RHE), outperforming all previously reported BHJ-based photocathodes in terms of PEC performance. The highest ratiometric power-saved efficiency of 3.7% is achieved at 0.4 V vs. RHE.
2023, 34(1): 107684
doi: 10.1016/j.cclet.2022.07.027
Abstract:
Developing non-conjugated luminescent polymers (NCLPs) with fluorescence and long-lived room-temperature phosphorescence is of great significance for revealing the essence of NCLPs luminescence, which has gradually attracted the attention of researchers in recent years. Herein, polymethylol (PMO) and poly(3-butene-1, 2-diol) (PBD) with polyhydroxy structures were prepared and their luminescence behaviors were investigated to reveal the clusteroluminescence (CL) mechanism. Compared with polyvinyl alcohol with non-luminescent behavior, PMO and PBD exhibit cyan-blue fluorescence with quantum yields of ca. 12% and green room-temperature phosphorescence with lifetimes of ca. 89 ms in the solid state. Both fluorescence and phosphorescence exhibit typical excitation-dependent CL behavior. Experimental and theoretical analyses show that the strong hydrogen-bonding interaction of PMO and PBD greatly promotes the formation of oxygen clusters and the through-space n-n interaction of oxygen atoms, enabling fluorescence and phosphorescence emission. Our results have enormous implications for understanding the CL mechanism of NCLPs and provide a new polymer design strategy for the rational design of novel NCLPs materials.
Developing non-conjugated luminescent polymers (NCLPs) with fluorescence and long-lived room-temperature phosphorescence is of great significance for revealing the essence of NCLPs luminescence, which has gradually attracted the attention of researchers in recent years. Herein, polymethylol (PMO) and poly(3-butene-1, 2-diol) (PBD) with polyhydroxy structures were prepared and their luminescence behaviors were investigated to reveal the clusteroluminescence (CL) mechanism. Compared with polyvinyl alcohol with non-luminescent behavior, PMO and PBD exhibit cyan-blue fluorescence with quantum yields of ca. 12% and green room-temperature phosphorescence with lifetimes of ca. 89 ms in the solid state. Both fluorescence and phosphorescence exhibit typical excitation-dependent CL behavior. Experimental and theoretical analyses show that the strong hydrogen-bonding interaction of PMO and PBD greatly promotes the formation of oxygen clusters and the through-space n-n interaction of oxygen atoms, enabling fluorescence and phosphorescence emission. Our results have enormous implications for understanding the CL mechanism of NCLPs and provide a new polymer design strategy for the rational design of novel NCLPs materials.
2023, 34(1): 107716
doi: 10.1016/j.cclet.2022.07.059
Abstract:
Phosphorylation plays crucial parts in lenticular biological function. Getting knowledge of region-resolved phosphoproteome contributes to better comprehending the pathogenesis. Here, we prepared the hybrid metal organic frameworks (HMOFs) for probing the region-resolved heterogeneity of phosphoproteome in human lens. 1334 phosphosites corresponding to 564 phosphoproteins, 1160 phosphosites corresponding to 316 phosphoproteins and 517 phosphosites corresponding to 205 phosphoproteins were identified in capsule, cortex and nucleus, respectively, providing the relatively extensive distribution mapping of phosphorylation in human lens for the first time. The label-free quantification experiments and principal component analysis presented differential expression of phopshoproteins in three subregions. For instance, α-crystallin, β-crystallin and fibrillin-1 closely associated with cataract and Marfan syndrome showed disparate spatial distribution. The preferential phosphoproteins in capsule, cortex and nucleus were involved in cytoskeleton organization, metabolic process and lens development in camera-type eye, respectively. This work first provided a general overview of region-resolved phosphoproteome of human lens.
Phosphorylation plays crucial parts in lenticular biological function. Getting knowledge of region-resolved phosphoproteome contributes to better comprehending the pathogenesis. Here, we prepared the hybrid metal organic frameworks (HMOFs) for probing the region-resolved heterogeneity of phosphoproteome in human lens. 1334 phosphosites corresponding to 564 phosphoproteins, 1160 phosphosites corresponding to 316 phosphoproteins and 517 phosphosites corresponding to 205 phosphoproteins were identified in capsule, cortex and nucleus, respectively, providing the relatively extensive distribution mapping of phosphorylation in human lens for the first time. The label-free quantification experiments and principal component analysis presented differential expression of phopshoproteins in three subregions. For instance, α-crystallin, β-crystallin and fibrillin-1 closely associated with cataract and Marfan syndrome showed disparate spatial distribution. The preferential phosphoproteins in capsule, cortex and nucleus were involved in cytoskeleton organization, metabolic process and lens development in camera-type eye, respectively. This work first provided a general overview of region-resolved phosphoproteome of human lens.
2023, 34(1): 107813
doi: 10.1016/j.cclet.2022.107813
Abstract:
Spin properties of organic molecules have attracted great interest for their potential applications in spintronic devices and quantum computing. Fe-tetraphenyl porphyrin (FeTPP) is of particular interest for its robust magnetic properties on metallic substrates. FeTPP is prepared in vacuum via on-surface synthesis. Molecular structure and spin-related transport properties are characterized by low-temperature scanning tunneling microscope and spectroscopy at 0.5 K. Density functional theory calculations are performed to understand molecular adsorption and spin distribution on Au(111). The molecular structure of FeTPP is distorted upon adsorption on the substrate. Spin excitations of FeTPP are observed on the Fe atom and high pyrrole groups in differential conductance spectra. The calculated spin density distribution indicates that the electron spin of FeTPP is mainly distributed on the Fe atom. The atomic transmission calculation indicates that electrons transport to substrate is mediated through Fe atom, when the tip is above the high pyrrole group.
Spin properties of organic molecules have attracted great interest for their potential applications in spintronic devices and quantum computing. Fe-tetraphenyl porphyrin (FeTPP) is of particular interest for its robust magnetic properties on metallic substrates. FeTPP is prepared in vacuum via on-surface synthesis. Molecular structure and spin-related transport properties are characterized by low-temperature scanning tunneling microscope and spectroscopy at 0.5 K. Density functional theory calculations are performed to understand molecular adsorption and spin distribution on Au(111). The molecular structure of FeTPP is distorted upon adsorption on the substrate. Spin excitations of FeTPP are observed on the Fe atom and high pyrrole groups in differential conductance spectra. The calculated spin density distribution indicates that the electron spin of FeTPP is mainly distributed on the Fe atom. The atomic transmission calculation indicates that electrons transport to substrate is mediated through Fe atom, when the tip is above the high pyrrole group.
2023, 34(1): 107761
doi: 10.1016/j.cclet.2022.107761
Abstract:
