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2021 Volume 32 Issue 10
2021, 32(10): 2923-2932
doi: 10.1016/j.cclet.2021.03.073
Abstract:
Soft and wet actuator systems have attracted great attention in some applications, such as assistive technologies for rehabilitation, training and regenerative biomedicines. Three-dimensional (3D) printing methods have realized the rapid fabrication of complex structures without the need for expensive dies or post processing. In this review, a comprehensive description is presented on stimuli-responsive hydrogels fabricated by light-responsive and extrusion-based 3D printing technologies. Mechanisms of actuations have been introduced based on stimuli types. As the most common method for 3D printed hydrogel actuators, direct-ink-writing has been discussed, including the two printing parameters of resolution and rheology. In addition, applications of 3D printed hydrogel actuators are presented followed by introductions of recent contributions on enhancing the toughness of 3D printed hydrogel and robust design tools, such as finite element analysis and artificial intelligence.
Soft and wet actuator systems have attracted great attention in some applications, such as assistive technologies for rehabilitation, training and regenerative biomedicines. Three-dimensional (3D) printing methods have realized the rapid fabrication of complex structures without the need for expensive dies or post processing. In this review, a comprehensive description is presented on stimuli-responsive hydrogels fabricated by light-responsive and extrusion-based 3D printing technologies. Mechanisms of actuations have been introduced based on stimuli types. As the most common method for 3D printed hydrogel actuators, direct-ink-writing has been discussed, including the two printing parameters of resolution and rheology. In addition, applications of 3D printed hydrogel actuators are presented followed by introductions of recent contributions on enhancing the toughness of 3D printed hydrogel and robust design tools, such as finite element analysis and artificial intelligence.
2021, 32(10): 2933-2938
doi: 10.1016/j.cclet.2021.03.047
Abstract:
Carbon-based selenium-containing materials are novel materials just being invented recently. Owing to the low cost and bio-compatible features of carbon and selenium, these materials are practical. The unique chemical- and bio-activities of selenium endow them wide range of applications in catalysis, environment-protection, fertilizer and biocide development etc. Recent progresses in this field are summarized and prospected from the engineering application viewpoint in this mini-review.
Carbon-based selenium-containing materials are novel materials just being invented recently. Owing to the low cost and bio-compatible features of carbon and selenium, these materials are practical. The unique chemical- and bio-activities of selenium endow them wide range of applications in catalysis, environment-protection, fertilizer and biocide development etc. Recent progresses in this field are summarized and prospected from the engineering application viewpoint in this mini-review.
2021, 32(10): 2939-2946
doi: 10.1016/j.cclet.2021.04.059
Abstract:
Biochar (BC) are widely used as highly efficient adsorbents to alleviate aromatics-based contaminants due to their ease of preparation, wide availability, and high sustainability. The surface properties of BCs usually vary greatly due to their complex chemical constituents and different preparation processes and are reflected in the values of parameters such as the specific surface area (SSA), pore volume/size, and surface functional groups (SFGs). The effects of SSA and pore volume/size on the adsorption of aromatics have been widely reported. However, the corresponding mechanisms of BC SFGs towards aromatics adsorption remains unclear as the compositions of the SFGs are usually complex and hard to determine. To address in this gap in the literature, this review introduces a new perspective on the adsorption mechanisms of aromatics. Through collecting previously-reported results, the parameters logP (logarithm of the Kow), polar surface area, and the positive/negative charges were carefully calculated using ChemDraw 3D, which allowed the hydrophobicity/hydrophilicity properties, electron donor-acceptor interactions, H-bonding, and electrostatic interactions between SFGs and aromatics-based contaminates to be inferred intuitively. These predictions were consistent with the reported results and showed that tailor-made BCs can be designed according to the molecular weights, chemical structures, and polarities of the target aromatics. Overall, this review provides new insight into predicting the physicochemical properties of BCs through revealing the relationship between SFGs and adsorbates, which may provide useful guidance for the preparing of highly-efficient, functional BCs for the adsorption of aromatics.
Biochar (BC) are widely used as highly efficient adsorbents to alleviate aromatics-based contaminants due to their ease of preparation, wide availability, and high sustainability. The surface properties of BCs usually vary greatly due to their complex chemical constituents and different preparation processes and are reflected in the values of parameters such as the specific surface area (SSA), pore volume/size, and surface functional groups (SFGs). The effects of SSA and pore volume/size on the adsorption of aromatics have been widely reported. However, the corresponding mechanisms of BC SFGs towards aromatics adsorption remains unclear as the compositions of the SFGs are usually complex and hard to determine. To address in this gap in the literature, this review introduces a new perspective on the adsorption mechanisms of aromatics. Through collecting previously-reported results, the parameters logP (logarithm of the Kow), polar surface area, and the positive/negative charges were carefully calculated using ChemDraw 3D, which allowed the hydrophobicity/hydrophilicity properties, electron donor-acceptor interactions, H-bonding, and electrostatic interactions between SFGs and aromatics-based contaminates to be inferred intuitively. These predictions were consistent with the reported results and showed that tailor-made BCs can be designed according to the molecular weights, chemical structures, and polarities of the target aromatics. Overall, this review provides new insight into predicting the physicochemical properties of BCs through revealing the relationship between SFGs and adsorbates, which may provide useful guidance for the preparing of highly-efficient, functional BCs for the adsorption of aromatics.
2021, 32(10): 2947-2962
doi: 10.1016/j.cclet.2021.03.082
Abstract:
Single atom catalyst (SAC) refers to a novel catalyst with the active metal atoms individually anchored on the support. Single atom catalysts present the unique appeal due to the high atomic availability and specific activity, as well as the high pathway selectivity. Herein, we summarized the classification, preparation, characterization, and application of single atom catalysts. Finally, the current bottlenecks and the outlooks of the SAC research are discussed.
Single atom catalyst (SAC) refers to a novel catalyst with the active metal atoms individually anchored on the support. Single atom catalysts present the unique appeal due to the high atomic availability and specific activity, as well as the high pathway selectivity. Herein, we summarized the classification, preparation, characterization, and application of single atom catalysts. Finally, the current bottlenecks and the outlooks of the SAC research are discussed.
2021, 32(10): 2963-2974
doi: 10.1016/j.cclet.2021.03.023
Abstract:
The simultaneous removal of SO2, NOx and Hg0 from industrial exhaust flue gas has drawn worldwide attention in recent years. A particularly attractive technique is selective catalytic reduction, which effectively removes SO2, NOx and Hg0 at low temperatures. This paper first reviews the simultaneous removal of SO2, NOx and Hg0 by unsupported and supported catalysts. It then describes and compares the research progress of various carriers, eg., carbon-based materials, metal oxides, silica, molecular sieves, metal-organic frameworks, and pillared interlayered clays, in the simultaneous removal of SO2, NOx and Hg0. The effects of flue-gas components (such as O2, NH3, HCl, H2O, SO2, NO, and Hg0) on the removal of SO2, NOx, and Hg0 are discussed comprehensively and systematically. After summarizing the pollutant-removal mechanism, the review discusses future developments in the simultaneous removal of SO2, NOx and Hg0 by catalysts.
The simultaneous removal of SO2, NOx and Hg0 from industrial exhaust flue gas has drawn worldwide attention in recent years. A particularly attractive technique is selective catalytic reduction, which effectively removes SO2, NOx and Hg0 at low temperatures. This paper first reviews the simultaneous removal of SO2, NOx and Hg0 by unsupported and supported catalysts. It then describes and compares the research progress of various carriers, eg., carbon-based materials, metal oxides, silica, molecular sieves, metal-organic frameworks, and pillared interlayered clays, in the simultaneous removal of SO2, NOx and Hg0. The effects of flue-gas components (such as O2, NH3, HCl, H2O, SO2, NO, and Hg0) on the removal of SO2, NOx, and Hg0 are discussed comprehensively and systematically. After summarizing the pollutant-removal mechanism, the review discusses future developments in the simultaneous removal of SO2, NOx and Hg0 by catalysts.
2021, 32(10): 2975-2984
doi: 10.1016/j.cclet.2021.02.058
Abstract:
Metal-organic frameworks (MOFs) are currently popular porous materials with research and application value in various fields. Aiming at the application of MOFs in photocatalysis, this paper mainly reviews the main synthesis methods of MOFs and the latest research progress of MOFs-based photocatalysts to degrade organic pollutants in water, such as organic dyes, pharmaceuticals and personal care products, and other organic pollutants. The main characteristics of different synthesis methods of MOFs, the main design strategies of MOFs-based photocatalysts, and the excellent performance of photocatalytic degradation of organic pollutants are summarized. At the end of this paper, the practical application of MOFs, the current limitations of MOFs, the synthesis methods of MOFs, and the future development trend of MOFs photocatalysts are explained.
Metal-organic frameworks (MOFs) are currently popular porous materials with research and application value in various fields. Aiming at the application of MOFs in photocatalysis, this paper mainly reviews the main synthesis methods of MOFs and the latest research progress of MOFs-based photocatalysts to degrade organic pollutants in water, such as organic dyes, pharmaceuticals and personal care products, and other organic pollutants. The main characteristics of different synthesis methods of MOFs, the main design strategies of MOFs-based photocatalysts, and the excellent performance of photocatalytic degradation of organic pollutants are summarized. At the end of this paper, the practical application of MOFs, the current limitations of MOFs, the synthesis methods of MOFs, and the future development trend of MOFs photocatalysts are explained.
2021, 32(10): 2985-2993
doi: 10.1016/j.cclet.2021.03.031
Abstract:
Ozone (O3) plays essential roles in stratosphere and helps reduce the amount of harmful ultraviolet arriving the Earth's surface. However, O3 is also a strong oxidant and causes troubles to human health in troposphere, especially in the confined space, such as indoor environment. Recently, O3 abatement materials have become research hotspots due to the urgent environmental demands. Catalysis is a facile strategy that can eliminate indoor airborne O3 efficiently and economically. Thus, this review summarizes the recent progresses of O3 decomposition catalysts. The catalysts covered here are categorized as follows: zeolite, metal organic frameworks (MOFs), metal oxides, noble metals. Manganese-based catalysts display higher efficiency and are mainly discussed. Generally, the active sites of O3 decomposition catalysts are described as Lewis acid sites (e.g., zeolite), metal sites (e.g., MOFs), oxygen vacancy sites (e.g., MnO2) in the previous work. In this review, we ascribe all the active sites to unsaturated metal sites and their Lewis acidity. Possible evidence from the experimental and theoretical perspectives are proposed. Furthermore, the strategy to circumvent deactivation caused by peroxides (O22-) accumulation and water molecular competition are also elaborated. Finally, perspective is presented on the challenges and opportunities of exploring existing and new O3 decomposition catalysts.
Ozone (O3) plays essential roles in stratosphere and helps reduce the amount of harmful ultraviolet arriving the Earth's surface. However, O3 is also a strong oxidant and causes troubles to human health in troposphere, especially in the confined space, such as indoor environment. Recently, O3 abatement materials have become research hotspots due to the urgent environmental demands. Catalysis is a facile strategy that can eliminate indoor airborne O3 efficiently and economically. Thus, this review summarizes the recent progresses of O3 decomposition catalysts. The catalysts covered here are categorized as follows: zeolite, metal organic frameworks (MOFs), metal oxides, noble metals. Manganese-based catalysts display higher efficiency and are mainly discussed. Generally, the active sites of O3 decomposition catalysts are described as Lewis acid sites (e.g., zeolite), metal sites (e.g., MOFs), oxygen vacancy sites (e.g., MnO2) in the previous work. In this review, we ascribe all the active sites to unsaturated metal sites and their Lewis acidity. Possible evidence from the experimental and theoretical perspectives are proposed. Furthermore, the strategy to circumvent deactivation caused by peroxides (O22-) accumulation and water molecular competition are also elaborated. Finally, perspective is presented on the challenges and opportunities of exploring existing and new O3 decomposition catalysts.
2021, 32(10): 2994-3006
doi: 10.1016/j.cclet.2021.03.078
Abstract:
Nanozymes are nanomaterials with enzyme-like activities that efficiently overcome the drawbacks of natural enzymes in biosensing, detection, and biomedical fields, and they are the most widely used artificial enzymes. Owing to their excellent catalytic characteristics, biocompatibility, and environmental favorability, carbon-dots-based (CDs) nanozymes have inspired a research upsurge. However, no review focusing on CDs nanozymes has been published, even though substantial advances have been achieved. Herein, the advances, catalytic activities, and applications of CDs nanozymes are highlighted and summarized. In addition, the critical issues and challenges of researching nanozymes are discussed. We hope that this review will broaden the horizons of nanozymes and CDs nanozymes, as well as promote their development.
Nanozymes are nanomaterials with enzyme-like activities that efficiently overcome the drawbacks of natural enzymes in biosensing, detection, and biomedical fields, and they are the most widely used artificial enzymes. Owing to their excellent catalytic characteristics, biocompatibility, and environmental favorability, carbon-dots-based (CDs) nanozymes have inspired a research upsurge. However, no review focusing on CDs nanozymes has been published, even though substantial advances have been achieved. Herein, the advances, catalytic activities, and applications of CDs nanozymes are highlighted and summarized. In addition, the critical issues and challenges of researching nanozymes are discussed. We hope that this review will broaden the horizons of nanozymes and CDs nanozymes, as well as promote their development.
2021, 32(10): 3007-3010
doi: 10.1016/j.cclet.2021.03.045
Abstract:
A new charge transfer cocrystal of 1, 2, 4, 5-tetracyanobenzene (TCNB)-phenazine (PTC) was prepared by solvent evaporation method. The donor and acceptor molecules of cocrystal are stacked face to face with a mixed-stacking, implying a strong charge transfer (CT) interactions in the cocrystal system. The spectroscopic studies, single-crystal X-ray diffraction structure, density functional theory (DFT) and Hirschfield surfaces calculations are carried out to explore the relationship between structure and properties of cocrystal system, which show that the intermolecular interactions in PTC are stronger than those of single components, leading to the stability and photophysical behaviors of cocrystal different from their constitute units. This study will be helpful for the design and preparation of multifunctional cocrystal materials.
A new charge transfer cocrystal of 1, 2, 4, 5-tetracyanobenzene (TCNB)-phenazine (PTC) was prepared by solvent evaporation method. The donor and acceptor molecules of cocrystal are stacked face to face with a mixed-stacking, implying a strong charge transfer (CT) interactions in the cocrystal system. The spectroscopic studies, single-crystal X-ray diffraction structure, density functional theory (DFT) and Hirschfield surfaces calculations are carried out to explore the relationship between structure and properties of cocrystal system, which show that the intermolecular interactions in PTC are stronger than those of single components, leading to the stability and photophysical behaviors of cocrystal different from their constitute units. This study will be helpful for the design and preparation of multifunctional cocrystal materials.
2021, 32(10): 3011-3014
doi: 10.1016/j.cclet.2021.03.046
Abstract:
A facile and efficient strategy was established for the construction of RC-529 and its derivatives. Four conjugates of RC-529 derivatives with Tn antigen were synthesized and all elicited strong and T cell-dependent immune responses in mice without requiring external adjuvants. In addition, all antisera induced by these conjugates could specifically recognize, bind to and kill Tn-overexpressing cancer cells. Thus, RC-529 shows promise as a useful platform for the development of new vaccine carriers with self-adjuvanting properties for the treatment of cancer. Moreover, preliminary structure-activity relationship analysis provides convincing support for further optimization of, and additional investigation into, RC-529.
A facile and efficient strategy was established for the construction of RC-529 and its derivatives. Four conjugates of RC-529 derivatives with Tn antigen were synthesized and all elicited strong and T cell-dependent immune responses in mice without requiring external adjuvants. In addition, all antisera induced by these conjugates could specifically recognize, bind to and kill Tn-overexpressing cancer cells. Thus, RC-529 shows promise as a useful platform for the development of new vaccine carriers with self-adjuvanting properties for the treatment of cancer. Moreover, preliminary structure-activity relationship analysis provides convincing support for further optimization of, and additional investigation into, RC-529.
2021, 32(10): 3015-3018
doi: 10.1016/j.cclet.2021.04.006
Abstract:
Density functional theory calculations have been performed to investigate the nickel-catalyzed [3 + 2] cycloaddition of cyclopropenones and α, β-unsaturated ketones. The computations show that the overall catalytic cycle consists of four major steps, including: (1) C-C oxidative addition of the cyclopropenone to afford the four-membered nickelacycle, (2) isomerization, (3) migratory insertion via a 4, 1-insertion fashion, and (4) C-C reductive elimination to deliver the [3 + 2] cycloaddition product. The enantioselectivity is mainly attributed to the π-π interaction between the diphenylcyclopropenone moiety and the phenyl substituent of the oxazoline ring of the ligand. The chemoselectivity of the C = O versus C = C insertion was rationalized in terms of the steric effect.
Density functional theory calculations have been performed to investigate the nickel-catalyzed [3 + 2] cycloaddition of cyclopropenones and α, β-unsaturated ketones. The computations show that the overall catalytic cycle consists of four major steps, including: (1) C-C oxidative addition of the cyclopropenone to afford the four-membered nickelacycle, (2) isomerization, (3) migratory insertion via a 4, 1-insertion fashion, and (4) C-C reductive elimination to deliver the [3 + 2] cycloaddition product. The enantioselectivity is mainly attributed to the π-π interaction between the diphenylcyclopropenone moiety and the phenyl substituent of the oxazoline ring of the ligand. The chemoselectivity of the C = O versus C = C insertion was rationalized in terms of the steric effect.
2021, 32(10): 3019-3022
doi: 10.1016/j.cclet.2021.04.008
Abstract:
The wide-spreading SARS-CoV-2 virus has put the world into boiling water for more than a year, however pharmacological therapies to act effectively against coronavirus disease 2019 (COVID-19) remain elusive. Chloroquine (CQ), an antimalarial drug, was found to exhibit promising antiviral activity in vitro and in vivo at a high dosage, thus CQ was approved by the FDA for the emergency use authorization (EUA) in the fight against COVID-19 in the US, but later was revoked the EUA status due to the severe clinical toxicity. Herein, we show that supramolecular formulation of CQ by a macrocyclic host, curcurbit[7]uril (CB[7]), reduced its non-specific toxicity and improved its antiviral activity against coronavirus, working in synergy with CB[7]. CB[7] was found to form 1:1 host-guest complexes with CQ, with a binding constant of ~104 L/mol. The CQ-CB[7] formulation decreased the cytotoxicity of CQ against Vero E6 and L-02 cell lines. In particular, the cytotoxicity of CQ (60 μmol/L) against both Vero E6 cell line and L-02 cell lines was completely inhibited in the presence of 300 μmol/L and 600 μmol/L CB[7], respectively. Furthermore, the CB[7] alone showed astonishing antiviral activity in SARS-CoV-2 infected Vero E6 cells and mouse hepatitis virus strain A59 (MHV-A59) infected N2A cells, and synergistically improved the antiviral activity of CQ-CB[7], suggesting that CB[7]-based CQ formulation has a great potential as a safe and effective antiviral agent against SARS-CoV-2 and other coronavirus.
The wide-spreading SARS-CoV-2 virus has put the world into boiling water for more than a year, however pharmacological therapies to act effectively against coronavirus disease 2019 (COVID-19) remain elusive. Chloroquine (CQ), an antimalarial drug, was found to exhibit promising antiviral activity in vitro and in vivo at a high dosage, thus CQ was approved by the FDA for the emergency use authorization (EUA) in the fight against COVID-19 in the US, but later was revoked the EUA status due to the severe clinical toxicity. Herein, we show that supramolecular formulation of CQ by a macrocyclic host, curcurbit[7]uril (CB[7]), reduced its non-specific toxicity and improved its antiviral activity against coronavirus, working in synergy with CB[7]. CB[7] was found to form 1:1 host-guest complexes with CQ, with a binding constant of ~104 L/mol. The CQ-CB[7] formulation decreased the cytotoxicity of CQ against Vero E6 and L-02 cell lines. In particular, the cytotoxicity of CQ (60 μmol/L) against both Vero E6 cell line and L-02 cell lines was completely inhibited in the presence of 300 μmol/L and 600 μmol/L CB[7], respectively. Furthermore, the CB[7] alone showed astonishing antiviral activity in SARS-CoV-2 infected Vero E6 cells and mouse hepatitis virus strain A59 (MHV-A59) infected N2A cells, and synergistically improved the antiviral activity of CQ-CB[7], suggesting that CB[7]-based CQ formulation has a great potential as a safe and effective antiviral agent against SARS-CoV-2 and other coronavirus.
2021, 32(10): 3023-3026
doi: 10.1016/j.cclet.2021.04.014
Abstract:
A convenient colorimetric approach for visual detection of melamine in raw milk was realized by using gold nanoparticles (AuNPs) stabilized by an unsymmetrical terpyridyl zinc complex with a thymine fragment at one terminal and a quaternary ammonium salt at the other. Even without pre-addition of melamine or relative additives, obvious color change from red to blue was observed by naked eye in the presence of trace amount of melamine, which was attributed to the alternation of aggregation state of AuNPs caused by the selective binding between the thymine fragment and melamine via triple hydrogen-bonding interactions. Remarkably, the detection limit for melamine was as low as 2.4 ppb, providing a highly sensitive and efficient approach for the visual detection of melamine.
A convenient colorimetric approach for visual detection of melamine in raw milk was realized by using gold nanoparticles (AuNPs) stabilized by an unsymmetrical terpyridyl zinc complex with a thymine fragment at one terminal and a quaternary ammonium salt at the other. Even without pre-addition of melamine or relative additives, obvious color change from red to blue was observed by naked eye in the presence of trace amount of melamine, which was attributed to the alternation of aggregation state of AuNPs caused by the selective binding between the thymine fragment and melamine via triple hydrogen-bonding interactions. Remarkably, the detection limit for melamine was as low as 2.4 ppb, providing a highly sensitive and efficient approach for the visual detection of melamine.
2021, 32(10): 3027-3030
doi: 10.1016/j.cclet.2021.03.070
Abstract:
We have developed a versatile, mild protocol for trifluoromethylthiolation reactions of aldehydes with catalysis by a decatungstate hydrogen atom transfer photocatalyst under redox-neutral conditions. The protocol is highly selective, operationally simple, and compatible with a wide array of sensitive functional groups. It can be used for late-stage functionalization of bioactive molecules, which makes it convenient for drug discovery.
We have developed a versatile, mild protocol for trifluoromethylthiolation reactions of aldehydes with catalysis by a decatungstate hydrogen atom transfer photocatalyst under redox-neutral conditions. The protocol is highly selective, operationally simple, and compatible with a wide array of sensitive functional groups. It can be used for late-stage functionalization of bioactive molecules, which makes it convenient for drug discovery.
2021, 32(10): 3031-3033
doi: 10.1016/j.cclet.2021.03.068
Abstract:
A new synthesis of the bridged [6-6-6] ABE tricyclic ring analogues of methyllycaconitine with the C-1 oxygenated substituents has been developed using an efficient aza-annulation of β-enamino ketone followed by a facile decarboxylation to form BE rings. Subsequent elaboration to form the A ring was achieved by a transannular acyl radical cyclization with concomitant equipment of the key C-1 oxygen functionality.
A new synthesis of the bridged [6-6-6] ABE tricyclic ring analogues of methyllycaconitine with the C-1 oxygenated substituents has been developed using an efficient aza-annulation of β-enamino ketone followed by a facile decarboxylation to form BE rings. Subsequent elaboration to form the A ring was achieved by a transannular acyl radical cyclization with concomitant equipment of the key C-1 oxygen functionality.
2021, 32(10): 3034-3038
doi: 10.1016/j.cclet.2021.03.079
Abstract:
Advanced chemotherapy strategies are in urgent demand for improving anticancer efficacy. Herein, a water-soluble pillar[6]arene (WP6A) was used to load chemotherapeutic agent pemetrexed (PMX) by forming direct host-guest inclusion, which is beneficial for decreasing cytotoxicity of PMX on BEAS-2B cells. NMR and florescence titration served to confirm the complexation between WP6A and ATP with higher affinity [(5.67 ± 0.31) × 105 L/mol], favoring competitive replacement of PMX. Complexation ATP by WP6A effectively prevented ATP from being hydrolyzed in presence of alkaline phosphatase. The formed host-guest complex was further used to block the efflux pump by cutting off energy source from ATP hydrolysis, which was accompanied with releasing PMX to produce synergistic enhancement of anticancer performance towards A549 cells. This supramolecular strategy would also be extended to other clinical chemotherapeutic agents and it was expected to provide salutary profits for cancer patients.
Advanced chemotherapy strategies are in urgent demand for improving anticancer efficacy. Herein, a water-soluble pillar[6]arene (WP6A) was used to load chemotherapeutic agent pemetrexed (PMX) by forming direct host-guest inclusion, which is beneficial for decreasing cytotoxicity of PMX on BEAS-2B cells. NMR and florescence titration served to confirm the complexation between WP6A and ATP with higher affinity [(5.67 ± 0.31) × 105 L/mol], favoring competitive replacement of PMX. Complexation ATP by WP6A effectively prevented ATP from being hydrolyzed in presence of alkaline phosphatase. The formed host-guest complex was further used to block the efflux pump by cutting off energy source from ATP hydrolysis, which was accompanied with releasing PMX to produce synergistic enhancement of anticancer performance towards A549 cells. This supramolecular strategy would also be extended to other clinical chemotherapeutic agents and it was expected to provide salutary profits for cancer patients.
2021, 32(10): 3039-3042
doi: 10.1016/j.cclet.2021.03.054
Abstract:
Numerous researchers have paid attention to achieve metal-free phosphorescence by exploring new structures or new mechanisms. Herein, a facile way is introduced to endow a common fluorescence dye, tetrabromofluorescein (4Br-Flu), some fabulous optical characteristics such as dual emission including thermally activated delayed fluorescence, room-temperature phosphorescence (RTP), and the excellent pH-sensitivity. Shortly, 4Br-Flu with good light-emitting properties is composed into the polymer system. The multiple bromine atoms promote the spin-orbit coupling effect and facilitate triplet excitation. Especially, the hydrogen bonding network of the polymer restricts the molecular motion of 4Br-Flu so that the system can emit long-wavelength RTP when 4Br-Flu is doped into polyvinyl alcohol or co-polymerized with acrylamide. Due to the reversible transformation of protonation and deprotonation, the 4Br-Flu based polymer responded to acid and alkali like a phosphorescent switch which makes it an excellent hydrogen chloride/ammonia gas leak detector in dry environment.
Numerous researchers have paid attention to achieve metal-free phosphorescence by exploring new structures or new mechanisms. Herein, a facile way is introduced to endow a common fluorescence dye, tetrabromofluorescein (4Br-Flu), some fabulous optical characteristics such as dual emission including thermally activated delayed fluorescence, room-temperature phosphorescence (RTP), and the excellent pH-sensitivity. Shortly, 4Br-Flu with good light-emitting properties is composed into the polymer system. The multiple bromine atoms promote the spin-orbit coupling effect and facilitate triplet excitation. Especially, the hydrogen bonding network of the polymer restricts the molecular motion of 4Br-Flu so that the system can emit long-wavelength RTP when 4Br-Flu is doped into polyvinyl alcohol or co-polymerized with acrylamide. Due to the reversible transformation of protonation and deprotonation, the 4Br-Flu based polymer responded to acid and alkali like a phosphorescent switch which makes it an excellent hydrogen chloride/ammonia gas leak detector in dry environment.
2021, 32(10): 3043-3047
doi: 10.1016/j.cclet.2021.03.060
Abstract:
Discrimination of glycoproteins and cell types is a significant but difficult issue. Herein, we presented a novel fluorescence sensor array for the detection and identification of glycoproteins and cancer cells based on the specific affinity between boronic acid-containing carbon dots (BA-CDs) and cis-diol residues of polysaccharides. The differential binding affinity of three BA-CDs to various glycoproteins resulted in a different fluorescence turn-on signal pattern caused by aggregation-enhanced emission (AEE), along with negligible response from other proteins. Therefore, BA-CDs encompassing sensing elements and signal indicator into one can enable a fast and accurate discrimination of glycoproteins with simple and easy operation. Seven glycoproteins could be well discriminated at a very low concentration of 10 nmol/L. The discriminating capability of glycoproteins is not sacrificed in both human urine and serum. Notably, different glycoprotein compositions of cancer cells provide more recognizable features for identification of cancer cells, comparing to the total protein. Five cell types could be identified in 15 min at a low concentration of 1000 cells/mL. This method is fast, accurate, and easy operation, and has a potential application in cancer diagnosis.
Discrimination of glycoproteins and cell types is a significant but difficult issue. Herein, we presented a novel fluorescence sensor array for the detection and identification of glycoproteins and cancer cells based on the specific affinity between boronic acid-containing carbon dots (BA-CDs) and cis-diol residues of polysaccharides. The differential binding affinity of three BA-CDs to various glycoproteins resulted in a different fluorescence turn-on signal pattern caused by aggregation-enhanced emission (AEE), along with negligible response from other proteins. Therefore, BA-CDs encompassing sensing elements and signal indicator into one can enable a fast and accurate discrimination of glycoproteins with simple and easy operation. Seven glycoproteins could be well discriminated at a very low concentration of 10 nmol/L. The discriminating capability of glycoproteins is not sacrificed in both human urine and serum. Notably, different glycoprotein compositions of cancer cells provide more recognizable features for identification of cancer cells, comparing to the total protein. Five cell types could be identified in 15 min at a low concentration of 1000 cells/mL. This method is fast, accurate, and easy operation, and has a potential application in cancer diagnosis.
2021, 32(10): 3048-3052
doi: 10.1016/j.cclet.2021.03.061
Abstract:
Carbon-based fluorescent nanomaterials have gained much attention in recent years. In this work, green-photoluminescent carbon nanodots (CNDs; also termed carbon dots, CDs) with amine termination were synthesized via the hydrothermal treatment of amine-containing spermine and rose bengal (RB) molecules. The CNDs have an ultrasmall size of ~2.2 nm and present bright photoluminescence with a high quantum yield of ~80% which is possibly attributed to the loss of halogen atoms (Cl and I) during the hydrothermal reaction. Different from most CNDs which have multicolor fluorescence emission, the as-prepared CNDs possess excitation-independent emission property, which can avoid fluorescence overlap with other fluorescent dyes. Moreover, the weakly basic amine-terminated surface endows the CNDs with the acidotropic effect. As a result, the CNDs can accumulate in the acidic lysosomes after cellular internalization and can serve as a favorable agent for lysosome imaging. Besides, the CNDs have a negligible impact on the lysosomal morphology even after 48 h incubation and exhibit excellent biocompatibility in the used cell models.
Carbon-based fluorescent nanomaterials have gained much attention in recent years. In this work, green-photoluminescent carbon nanodots (CNDs; also termed carbon dots, CDs) with amine termination were synthesized via the hydrothermal treatment of amine-containing spermine and rose bengal (RB) molecules. The CNDs have an ultrasmall size of ~2.2 nm and present bright photoluminescence with a high quantum yield of ~80% which is possibly attributed to the loss of halogen atoms (Cl and I) during the hydrothermal reaction. Different from most CNDs which have multicolor fluorescence emission, the as-prepared CNDs possess excitation-independent emission property, which can avoid fluorescence overlap with other fluorescent dyes. Moreover, the weakly basic amine-terminated surface endows the CNDs with the acidotropic effect. As a result, the CNDs can accumulate in the acidic lysosomes after cellular internalization and can serve as a favorable agent for lysosome imaging. Besides, the CNDs have a negligible impact on the lysosomal morphology even after 48 h incubation and exhibit excellent biocompatibility in the used cell models.
2021, 32(10): 3053-3056
doi: 10.1016/j.cclet.2021.03.056
Abstract:
A NIR fluorescent probe (DDAA) derived from fluorophore DDAO with alanine as the recognition group was developed for sensing aminopeptidase N (APN) in gut microbiota. Using DDAA as the real-time guidance tool for the fluorescence imaging of intestinal microorganism, target bacteria and saccharomycete possessing active APN were identified successfully from human feces.
A NIR fluorescent probe (DDAA) derived from fluorophore DDAO with alanine as the recognition group was developed for sensing aminopeptidase N (APN) in gut microbiota. Using DDAA as the real-time guidance tool for the fluorescence imaging of intestinal microorganism, target bacteria and saccharomycete possessing active APN were identified successfully from human feces.
2021, 32(10): 3057-3060
doi: 10.1016/j.cclet.2021.03.074
Abstract:
Intracellular pH is a key parameter related to various biological and pathological processes. In this study, a ratiometric pH fluorescent sensor ABTT was developed harnessing the amino-type excited-state intramolecular proton transfer (ESIPT) process. Relying on whether the ESIPT proceeds normally or not, ABTT exhibited the yellow fluorescence in acidic media, or cyan fluorescence in basic condition. According to the variation, ABTT behaved as a promising sensor which possessed fast and reversible response to pH change without interference from the biological substances, and exported a steady ratiometric signal (I478/I546). Moreover, due to the ESIPT effect, large Stokes shift and high quantum yield were also exhibited in ABTT. Furthermore, ABTT was applied for monitoring the pH changes in living cells and visualizing the pH fluctuations under oxidative stress successfully. These results elucidated great potential of ABTT in understanding pH-dependent physiological and pathological processes.
Intracellular pH is a key parameter related to various biological and pathological processes. In this study, a ratiometric pH fluorescent sensor ABTT was developed harnessing the amino-type excited-state intramolecular proton transfer (ESIPT) process. Relying on whether the ESIPT proceeds normally or not, ABTT exhibited the yellow fluorescence in acidic media, or cyan fluorescence in basic condition. According to the variation, ABTT behaved as a promising sensor which possessed fast and reversible response to pH change without interference from the biological substances, and exported a steady ratiometric signal (I478/I546). Moreover, due to the ESIPT effect, large Stokes shift and high quantum yield were also exhibited in ABTT. Furthermore, ABTT was applied for monitoring the pH changes in living cells and visualizing the pH fluctuations under oxidative stress successfully. These results elucidated great potential of ABTT in understanding pH-dependent physiological and pathological processes.
2021, 32(10): 3061-3065
doi: 10.1016/j.cclet.2021.03.075
Abstract:
Gastric ulcers are one of the most common stomach diseases that often accompanied by inflammation, congestion, edema, scar tissue formation, and pyloric obstruction. Fiberoptic endoscopy and X-ray analysis of the upper GI tract have become the diagnostic procedure of choice for patients. However, conventional diagnosis technology is either invasive or radioactive. Herein, a novel CD-MOF NIR-II fluorophore (GPs-CH1055) was developed. The relative fluorophore intensity was largely consistent at various media and pH buffers, and it can swell into gel particles in solvents and be completely expelled from the gastrointestinal tract without being assimilated. GPs-CH1055 has been further evaluated in vivo, and exhibited strong retention effect on the gastric ulcer sites, bright NIR-II signals with high spatial and temporal resolution. Therefore, GPs-CH1055 shows great promise for realizing real-time gastric ulcer imaging and diagnosis.
Gastric ulcers are one of the most common stomach diseases that often accompanied by inflammation, congestion, edema, scar tissue formation, and pyloric obstruction. Fiberoptic endoscopy and X-ray analysis of the upper GI tract have become the diagnostic procedure of choice for patients. However, conventional diagnosis technology is either invasive or radioactive. Herein, a novel CD-MOF NIR-II fluorophore (GPs-CH1055) was developed. The relative fluorophore intensity was largely consistent at various media and pH buffers, and it can swell into gel particles in solvents and be completely expelled from the gastrointestinal tract without being assimilated. GPs-CH1055 has been further evaluated in vivo, and exhibited strong retention effect on the gastric ulcer sites, bright NIR-II signals with high spatial and temporal resolution. Therefore, GPs-CH1055 shows great promise for realizing real-time gastric ulcer imaging and diagnosis.
2021, 32(10): 3066-3070
doi: 10.1016/j.cclet.2021.03.076
Abstract:
A series of probes KJ-x (x = 1−3) with carbon chains of different lengths based on the matrix of rhodamine B were engineered to detect Ag+ in aqueous solution in this work. Among them, KJ-1 is selected as the best option after in vitro investigation in view of its most sensitive and rapid response to Ag+, whose possible sensing mechanism is studied by experimental investigation and theoretical calculation. To identify the practical application of the probe, the detection of Ag+ in nonantibiotic fungicide Silver & Health and differentiation between normal hepatocytes and hepatoma cells using confocal imaging was conducted.
A series of probes KJ-x (x = 1−3) with carbon chains of different lengths based on the matrix of rhodamine B were engineered to detect Ag+ in aqueous solution in this work. Among them, KJ-1 is selected as the best option after in vitro investigation in view of its most sensitive and rapid response to Ag+, whose possible sensing mechanism is studied by experimental investigation and theoretical calculation. To identify the practical application of the probe, the detection of Ag+ in nonantibiotic fungicide Silver & Health and differentiation between normal hepatocytes and hepatoma cells using confocal imaging was conducted.
2021, 32(10): 3071-3075
doi: 10.1016/j.cclet.2021.03.085
Abstract:
Codelivery of drugs by drug carriers is a promising strategy against several diseases such as infections and cancer. However, traditional drug carriers are typically characterized by low drug payload, limiting their treatment efficacy. Using nanocrystals of insoluble drug as carriers, a carrier free platform was developed previously to deliver a second insoluble drug for codelivery. To extend the concept, we hypothesized, herein, that the platform allows for codelivery of hydrophobic and hydrophilic drugs using a cocrystalization-like strategy. To obtain proof-of-concept, paclitaxel (PTX), an insoluble chemotherapeutic agent, and dichloroacetic acid (DCA), a water-soluble inhibitor of pyruvate dehydrogenase kinase, were utilized as model drugs. PTX-DCA hybrid nanocrystals (PTX-DCA NCs) were prepared by anti-solvent precipitation and characterized. Their in vitro antitumor activity against cancer cells was evaluated. PTX-DCA NCs prepared from the optimized formulation had a diameter of 160 nm and a rod-shape morphology and possessed encapsulated efficacy of approximately 30% for DCA. The use of the hybrid crystals enabled synergy to kill cancer cells, in particular in PTX-resistant cells in a dose-dependent pattern. In conclusion, by using a cocrystalization-like strategy, a hydrophilic drug can be formulated into a drug's nanocrystal for codelivery.
Codelivery of drugs by drug carriers is a promising strategy against several diseases such as infections and cancer. However, traditional drug carriers are typically characterized by low drug payload, limiting their treatment efficacy. Using nanocrystals of insoluble drug as carriers, a carrier free platform was developed previously to deliver a second insoluble drug for codelivery. To extend the concept, we hypothesized, herein, that the platform allows for codelivery of hydrophobic and hydrophilic drugs using a cocrystalization-like strategy. To obtain proof-of-concept, paclitaxel (PTX), an insoluble chemotherapeutic agent, and dichloroacetic acid (DCA), a water-soluble inhibitor of pyruvate dehydrogenase kinase, were utilized as model drugs. PTX-DCA hybrid nanocrystals (PTX-DCA NCs) were prepared by anti-solvent precipitation and characterized. Their in vitro antitumor activity against cancer cells was evaluated. PTX-DCA NCs prepared from the optimized formulation had a diameter of 160 nm and a rod-shape morphology and possessed encapsulated efficacy of approximately 30% for DCA. The use of the hybrid crystals enabled synergy to kill cancer cells, in particular in PTX-resistant cells in a dose-dependent pattern. In conclusion, by using a cocrystalization-like strategy, a hydrophilic drug can be formulated into a drug's nanocrystal for codelivery.
2021, 32(10): 3076-3082
doi: 10.1016/j.cclet.2021.03.084
Abstract:
Chemotherapy is one of the most conventional modalities for cancer therapy. However, the high multidrug resistance of tumor cells still limited the clinical application of current chemotherapy. Considering the ability of nitric oxide (NO) to modulate potent P-glycoprotein to inhibit multi-drug resistance, a synergistic methodology combining chemotherapy and sustained NO generation is an ideal way to further promote the chemotherapy. Herein, a multi-functional micelle with tumor-selective chemotherapy driven by redox-triggered doxorubicin (DOX) release and drug resistance inhibition based on intracellular NO generation was fabricated for effective tumor treatment. The micelle consists of DOX as core, arginine/glucose oxidase (Arg/GOx) as shell and redox-responsive disulfide bond as a linker, which is denoted as micelle-DOX-Arg-GOx. The Arg serves as the biological precursor of nitric oxide for inhibition of multi-drug resistance to promote chemotherapy and GOx catalyzes glucose to produce hydrogen peroxide (H2O2) for increasing the generation of NO. Moreover, the glucose supply could be simultaneously blocked by the catalytic process, which further enhanced therapeutic efficiency. This micelle requests a tumor-specific microenvironment (a considerable amount of GSH) to perform synergistic therapeutics including chemotherapy, starvation therapy (catalytic medicine), and gas therapy for tumor treatment, which resulted in significant cytotoxicity to tumor tissue.
Chemotherapy is one of the most conventional modalities for cancer therapy. However, the high multidrug resistance of tumor cells still limited the clinical application of current chemotherapy. Considering the ability of nitric oxide (NO) to modulate potent P-glycoprotein to inhibit multi-drug resistance, a synergistic methodology combining chemotherapy and sustained NO generation is an ideal way to further promote the chemotherapy. Herein, a multi-functional micelle with tumor-selective chemotherapy driven by redox-triggered doxorubicin (DOX) release and drug resistance inhibition based on intracellular NO generation was fabricated for effective tumor treatment. The micelle consists of DOX as core, arginine/glucose oxidase (Arg/GOx) as shell and redox-responsive disulfide bond as a linker, which is denoted as micelle-DOX-Arg-GOx. The Arg serves as the biological precursor of nitric oxide for inhibition of multi-drug resistance to promote chemotherapy and GOx catalyzes glucose to produce hydrogen peroxide (H2O2) for increasing the generation of NO. Moreover, the glucose supply could be simultaneously blocked by the catalytic process, which further enhanced therapeutic efficiency. This micelle requests a tumor-specific microenvironment (a considerable amount of GSH) to perform synergistic therapeutics including chemotherapy, starvation therapy (catalytic medicine), and gas therapy for tumor treatment, which resulted in significant cytotoxicity to tumor tissue.
2021, 32(10): 3083-3086
doi: 10.1016/j.cclet.2021.05.018
Abstract:
The widespread applications of aggregation-induced emission luminogens (AIEgens) inspire the creation of AIEgens with novel structures and functionalities. In this work, we focused on the direct and efficient synthesis of a new type of AIEgens, imidazo[1, 5-a]pyridicne derivatives, via iodine mediated cascade oxidative Csp2–H or Csp–H amination route from phenylacetylene or styrenes under mild conditions. The resulted compounds showed excellent AIE characteristics with tunable maximum emissions, attractive bioimaging performance, and potential anti-inflammatory activity, which exert broad application prospects in material, biology, medicine, and other relevant areas.
The widespread applications of aggregation-induced emission luminogens (AIEgens) inspire the creation of AIEgens with novel structures and functionalities. In this work, we focused on the direct and efficient synthesis of a new type of AIEgens, imidazo[1, 5-a]pyridicne derivatives, via iodine mediated cascade oxidative Csp2–H or Csp–H amination route from phenylacetylene or styrenes under mild conditions. The resulted compounds showed excellent AIE characteristics with tunable maximum emissions, attractive bioimaging performance, and potential anti-inflammatory activity, which exert broad application prospects in material, biology, medicine, and other relevant areas.
2021, 32(10): 3087-3089
doi: 10.1016/j.cclet.2021.03.081
Abstract:
Tumor cells usually show abnormally high glycolysis rate to maintain the dynamic balance of energy. The growth of tumor cells can be affected by inhibiting the activity of pyruvate kinase (especially M2-type isozyme, PKM2), the rate limiting enzyme of glycolysis. This is helpful to the treatment of tumor. Herein, metal organic frameworks (MOFs) were found to inhibit the activity of PKM2. Nanoscale ZIF-8 was synthesized by standing and ultrasonic method, respectively. The ZIF-8 has the performance of inhibiting PKM2. Further research showed that the inhibition ability was attributed to zinc ion in ZIF-8. Interestingly, the IC50 of ZIF-8 on PKM2 was one percent of that of zinc ion. This novel enzyme inhibitor is expected to be used in cancer therapy.
Tumor cells usually show abnormally high glycolysis rate to maintain the dynamic balance of energy. The growth of tumor cells can be affected by inhibiting the activity of pyruvate kinase (especially M2-type isozyme, PKM2), the rate limiting enzyme of glycolysis. This is helpful to the treatment of tumor. Herein, metal organic frameworks (MOFs) were found to inhibit the activity of PKM2. Nanoscale ZIF-8 was synthesized by standing and ultrasonic method, respectively. The ZIF-8 has the performance of inhibiting PKM2. Further research showed that the inhibition ability was attributed to zinc ion in ZIF-8. Interestingly, the IC50 of ZIF-8 on PKM2 was one percent of that of zinc ion. This novel enzyme inhibitor is expected to be used in cancer therapy.
2021, 32(10): 3090-3094
doi: 10.1016/j.cclet.2021.02.056
Abstract:
The Co@NCNTs/Si pillars with channels is assemble to a suitable pure water gathering device, which is applied in seawater desalination and sewage purification to produce pure water by utilizing solar energy. High-efficiency utilization of solar energy to generate water vapor is popular, recyclable, and environmentally friendly for seawater desalination and sewage purification, helping to alleviate the global water shortage crisis. Here, we report an efficient and simple method to prepare a three-dimensional (3D) evaporator for steam generation by harnessing the power of the sun. This evaporation is composed of one-dimensional (1D) cobalt embedded and nitrogen doped carbon nanotubes (Co@NCNTs) and 3D silicon pillars array structure (Si pillars). The Co@NCNTs/Si pillars shows a wide light absorption range provided by carbon nanotubes and a long light absorption path because of the silicon pillars. The surface temperature of the sample rises rapidly in 1.5 min and exceed 80 ℃ under solar illumination of one sun. The water evaporation can be high as 1.21 kg m−2 h−1 under one sun irradiation (1 kW/m2) with the energy efficiency up to 82.4%. This scalable Co@NCNTs/Si pillars can prepare pure water from seawater and sewage, where the removal rate of ions in seawater and pollutants in sewage is similar to 100%. Based on our research, this multistage three-dimensional structure is a simple and efficient novel photothermal material for extensive seawater desalination and sewage purification.
The Co@NCNTs/Si pillars with channels is assemble to a suitable pure water gathering device, which is applied in seawater desalination and sewage purification to produce pure water by utilizing solar energy. High-efficiency utilization of solar energy to generate water vapor is popular, recyclable, and environmentally friendly for seawater desalination and sewage purification, helping to alleviate the global water shortage crisis. Here, we report an efficient and simple method to prepare a three-dimensional (3D) evaporator for steam generation by harnessing the power of the sun. This evaporation is composed of one-dimensional (1D) cobalt embedded and nitrogen doped carbon nanotubes (Co@NCNTs) and 3D silicon pillars array structure (Si pillars). The Co@NCNTs/Si pillars shows a wide light absorption range provided by carbon nanotubes and a long light absorption path because of the silicon pillars. The surface temperature of the sample rises rapidly in 1.5 min and exceed 80 ℃ under solar illumination of one sun. The water evaporation can be high as 1.21 kg m−2 h−1 under one sun irradiation (1 kW/m2) with the energy efficiency up to 82.4%. This scalable Co@NCNTs/Si pillars can prepare pure water from seawater and sewage, where the removal rate of ions in seawater and pollutants in sewage is similar to 100%. Based on our research, this multistage three-dimensional structure is a simple and efficient novel photothermal material for extensive seawater desalination and sewage purification.
2021, 32(10): 3095-3098
doi: 10.1016/j.cclet.2021.03.008
Abstract:
A highly stable fluorescent terbium MOF (Tb4(paip)6·1.2H2O, paip=5-(1H-pyrazole-4-yl)isophthalate) showing a sharp green emission (545 nm) and a quantum yield of 21.0% was successfully synthesized. This compound is shown to be a recyclable sensor for detecting picric acid in aqueous solution with both high sensitivity and selectivity, attributed to the electron transfer quenching mechanism.
A highly stable fluorescent terbium MOF (Tb4(paip)6·1.2H2O, paip=5-(1H-pyrazole-4-yl)isophthalate) showing a sharp green emission (545 nm) and a quantum yield of 21.0% was successfully synthesized. This compound is shown to be a recyclable sensor for detecting picric acid in aqueous solution with both high sensitivity and selectivity, attributed to the electron transfer quenching mechanism.
2021, 32(10): 3099-3104
doi: 10.1016/j.cclet.2021.03.039
Abstract:
Recently discovered bismuth oxychalcogenide (Bi2O2Se) has aroused great interest due to its ultrahigh carrier mobility, tunable band gap and good environmental stability, making it a promising candidate for high-performance electronics and optoelectronics. Their synthesis by colloidal approaches represents a cost-effective alternative to well-established chemical vapor deposition methods, and the resulting electronic-grade inks are important for large-area printed or wearable electronics. However, it is still challenging to control the colloidal growth of Bi2O2Se nanosheets in solution in addition to their assembly into high-performance thin films. Here, we report a two-step colloidal synthesis of Bi2O2Se nanosheets by separating the seeding and growth steps, thereby achieving controllable production of nanosheets with a lateral size of 1.4 μm and a thickness of 10 nm at optimized reaction conditions. These Bi2O2Se nanosheets are electrostatically assembled into large-area thin films, from which a photodetector is fabricated with a responsivity of 6.1 A/W and a short response time of 368 μs under the 520-nm laser illumination. The device exhibits fast response to modulations as high as 100 kHz, along with a −3 dB bandwidth of 1 kHz. This work provides an important understanding of the controlled colloidal synthesis of Bi2O2Se nanosheets, and demonstrates their potential applications in fast photodetectors.
Recently discovered bismuth oxychalcogenide (Bi2O2Se) has aroused great interest due to its ultrahigh carrier mobility, tunable band gap and good environmental stability, making it a promising candidate for high-performance electronics and optoelectronics. Their synthesis by colloidal approaches represents a cost-effective alternative to well-established chemical vapor deposition methods, and the resulting electronic-grade inks are important for large-area printed or wearable electronics. However, it is still challenging to control the colloidal growth of Bi2O2Se nanosheets in solution in addition to their assembly into high-performance thin films. Here, we report a two-step colloidal synthesis of Bi2O2Se nanosheets by separating the seeding and growth steps, thereby achieving controllable production of nanosheets with a lateral size of 1.4 μm and a thickness of 10 nm at optimized reaction conditions. These Bi2O2Se nanosheets are electrostatically assembled into large-area thin films, from which a photodetector is fabricated with a responsivity of 6.1 A/W and a short response time of 368 μs under the 520-nm laser illumination. The device exhibits fast response to modulations as high as 100 kHz, along with a −3 dB bandwidth of 1 kHz. This work provides an important understanding of the controlled colloidal synthesis of Bi2O2Se nanosheets, and demonstrates their potential applications in fast photodetectors.
2021, 32(10): 3105-3108
doi: 10.1016/j.cclet.2021.03.044
Abstract:
Lightweight, highly strong and bio-based structural materials remain a long-lasting challenge. Here, inspired by nacre, a lightweight and high mechanical performance cellulosic material was fabricated via a facile and effective top-down approach and the resulting material has a high tensile strength of 149.21MPa and toughness of 1.91 MJ/m3. More specifically, the natural balsawood (NW) was subjected to a simple chemical treatment, removing most lignin and partial hemicellulose, follow by freeze-drying, forming wood aerogel (WA). The delignification process produced many pores and exposed numerous aligned cellulose nanofibers. Afterwards, the WA absorbed a quantity of moisture and was directly densified to form above high-performance cellulosic material. Such treatment imitates highly ordered "brick-and-mortar" arrangement of nacre, in which water molecules plays the role of mortar and cellulose nanofibrils make the brick part. The lightweight and good mechanical properties make this material promising for new energy car, aerospace, etc. This paper also explains the strengthening mechanism for making biomimetic materials by water molecules-induced hydrogen bonding and will open a new path for designing high-performance bio-based structural materials.
Lightweight, highly strong and bio-based structural materials remain a long-lasting challenge. Here, inspired by nacre, a lightweight and high mechanical performance cellulosic material was fabricated via a facile and effective top-down approach and the resulting material has a high tensile strength of 149.21MPa and toughness of 1.91 MJ/m3. More specifically, the natural balsawood (NW) was subjected to a simple chemical treatment, removing most lignin and partial hemicellulose, follow by freeze-drying, forming wood aerogel (WA). The delignification process produced many pores and exposed numerous aligned cellulose nanofibers. Afterwards, the WA absorbed a quantity of moisture and was directly densified to form above high-performance cellulosic material. Such treatment imitates highly ordered "brick-and-mortar" arrangement of nacre, in which water molecules plays the role of mortar and cellulose nanofibrils make the brick part. The lightweight and good mechanical properties make this material promising for new energy car, aerospace, etc. This paper also explains the strengthening mechanism for making biomimetic materials by water molecules-induced hydrogen bonding and will open a new path for designing high-performance bio-based structural materials.
2021, 32(10): 3109-3112
doi: 10.1016/j.cclet.2021.03.043
Abstract:
A novel hydrogen-bonded organic frameworks (HOFs) FJU-200 has been constructed from N, N'-bis(5-isophthalic acid)naphthalimide (H4L). FJU-200 has a good dual-function of aniline and ultraviolet detection. FJU-200 is the first case of HOF with dual sensing of visual color changes and photoluminescence quenching for aniline detection, and the detection limit of aniline can reach 5.5 × 10−4 mol/L. Under ultraviolet FJU-200 will rapidly change from light yellow to rustic brown, which makes it possible to use FJU-200 to achieve minute-level ultraviolet detection. Moreover, for more convenient use, FJU-200 test papers are prepared. Using them, convenient and fast aniline or ultraviolet detection can be realized. The single-crystal X-ray structures show that compared with the original FJU-200, both and UV-FJU-200 have larger pore sizes, and the dihedral angles of the H2L2− in framework has been changed.
A novel hydrogen-bonded organic frameworks (HOFs) FJU-200 has been constructed from N, N'-bis(5-isophthalic acid)naphthalimide (H4L). FJU-200 has a good dual-function of aniline and ultraviolet detection. FJU-200 is the first case of HOF with dual sensing of visual color changes and photoluminescence quenching for aniline detection, and the detection limit of aniline can reach 5.5 × 10−4 mol/L. Under ultraviolet FJU-200 will rapidly change from light yellow to rustic brown, which makes it possible to use FJU-200 to achieve minute-level ultraviolet detection. Moreover, for more convenient use, FJU-200 test papers are prepared. Using them, convenient and fast aniline or ultraviolet detection can be realized. The single-crystal X-ray structures show that compared with the original FJU-200, both and UV-FJU-200 have larger pore sizes, and the dihedral angles of the H2L2− in framework has been changed.
2021, 32(10): 3113-3117
doi: 10.1016/j.cclet.2021.03.014
Abstract:
The research of borate materials as sodium-ion batteries (SIBs) anode is still in the early stages, but the boron polyoxoanions are attracting intense interest due to their low atomic weight and high electronegative features. In this work, FeBO3 was prepared with low-cost raw materials and evaluated as SIBs anode. The FeBO3 shows a high reversible capacity of 328 mAh/g at the current density of 0.4 A/g. In addition, the electrochemical performance of FeBO3 can be improved by carbon coating. The prepared carbon-coated FeBO3 composite has a reversible capacity of 426 mAh/g (at 0.4 A/g) and an outstanding rate capability of 272 mAh/g (at 1.6 A/g). Furthermore, the sodium storage mechanism of FeBO3 was studied by in-situ XRD and ex-situ XPS.
The research of borate materials as sodium-ion batteries (SIBs) anode is still in the early stages, but the boron polyoxoanions are attracting intense interest due to their low atomic weight and high electronegative features. In this work, FeBO3 was prepared with low-cost raw materials and evaluated as SIBs anode. The FeBO3 shows a high reversible capacity of 328 mAh/g at the current density of 0.4 A/g. In addition, the electrochemical performance of FeBO3 can be improved by carbon coating. The prepared carbon-coated FeBO3 composite has a reversible capacity of 426 mAh/g (at 0.4 A/g) and an outstanding rate capability of 272 mAh/g (at 1.6 A/g). Furthermore, the sodium storage mechanism of FeBO3 was studied by in-situ XRD and ex-situ XPS.
2021, 32(10): 3118-3122
doi: 10.1016/j.cclet.2021.03.048
Abstract:
The successful applications of two-dimensional (2D) transition metal dichalcogenides highly rely on rational regulation of their electronic properties. The nondestructive and controllable doping strategy is of great importance to implement 2D materials in electronic devices. Herein, we propose a straightforward and effective method to realize controllable n-type doping in WSe2 monolayer by electron beam irradiation. Electrical measurements and photoluminescence (PL) spectra verify the strong n-doping in electron beam-treated WSe2 monolayers. The n-type doping arises from the generation of Se vacancies and the doping degree is precisely controlled by irradiation fluences. Due to the n-doping-induced narrowing of the Schottky barrier, the current of back-gated monolayer WSe2 is enhanced by an order of magnitude and a ~8 × increase in the electron filed-effect mobility is observed. Remarkably, it is a moderate method without significant reduction in electrical performance and severe damage to lattice structures even under ultra-high doses of irradiation.
The successful applications of two-dimensional (2D) transition metal dichalcogenides highly rely on rational regulation of their electronic properties. The nondestructive and controllable doping strategy is of great importance to implement 2D materials in electronic devices. Herein, we propose a straightforward and effective method to realize controllable n-type doping in WSe2 monolayer by electron beam irradiation. Electrical measurements and photoluminescence (PL) spectra verify the strong n-doping in electron beam-treated WSe2 monolayers. The n-type doping arises from the generation of Se vacancies and the doping degree is precisely controlled by irradiation fluences. Due to the n-doping-induced narrowing of the Schottky barrier, the current of back-gated monolayer WSe2 is enhanced by an order of magnitude and a ~8 × increase in the electron filed-effect mobility is observed. Remarkably, it is a moderate method without significant reduction in electrical performance and severe damage to lattice structures even under ultra-high doses of irradiation.
2021, 32(10): 3123-3127
doi: 10.1016/j.cclet.2021.03.050
Abstract:
Metal–organic frameworks (MOFs) have a regular porous structure and high porosity, which make them ideal electrode materials for supercapacitors. However, their capacitance performance is greatly limited by their poor conductivity. In this study, a multi-component hierarchical structure was obtained by growing NiCoFeLDH on the surface of ZIF-67, which increased the electron transfer between the MOF particles and greatly improved the capacitance of ZIF-67. The formation mechanism of the multi-component layered hollow structure indicated that the hydrolysis acidity of metal ions and the coordination ability with ligands were the key factors for forming nanosheets and hollow structures. By controlling the type and valence state of the doped metals and the reaction time, the morphology transformation of MOF composites can be effectively controlled. Electrochemical studies showed that the specific capacitance of hollow NiCoFeLDH@ZIF-67 composite is 1202.08F/g (0.5 A/g). In addition, aqueous devices were assembled and carefully tested. This scheme is crucial for the design of MOF-based materials used in supercapacitor devices and serves as a guide for the design of MOF-based composites.
Metal–organic frameworks (MOFs) have a regular porous structure and high porosity, which make them ideal electrode materials for supercapacitors. However, their capacitance performance is greatly limited by their poor conductivity. In this study, a multi-component hierarchical structure was obtained by growing NiCoFeLDH on the surface of ZIF-67, which increased the electron transfer between the MOF particles and greatly improved the capacitance of ZIF-67. The formation mechanism of the multi-component layered hollow structure indicated that the hydrolysis acidity of metal ions and the coordination ability with ligands were the key factors for forming nanosheets and hollow structures. By controlling the type and valence state of the doped metals and the reaction time, the morphology transformation of MOF composites can be effectively controlled. Electrochemical studies showed that the specific capacitance of hollow NiCoFeLDH@ZIF-67 composite is 1202.08F/g (0.5 A/g). In addition, aqueous devices were assembled and carefully tested. This scheme is crucial for the design of MOF-based materials used in supercapacitor devices and serves as a guide for the design of MOF-based composites.
2021, 32(10): 3128-3132
doi: 10.1016/j.cclet.2021.03.057
Abstract:
Low-efficiency charge transfer is a critical factor to limit the photocatalytic H2 evolution activity of semiconductor photocatalysts. The interface design is a promising approach to achieve high charge-transfer efficiency for photocatalysts. Herein, a new 2D/2D atomic double-layer WS2/Nb2O5 shell/core photocatalyst (DLWS/Nb2O5) is designed. The atom-resolved HAADF-STEM results unravel the presence of an unusual 2D/2D shell/core interface in DLWS/Nb2O5. Taking advantage of the advanced femtosecond-resolved ultrafast TAS spectra, the average lifetime of charge carriers for DLWS/Nb2O5 (180.97 ps) is considerably shortened as compared to that of Nb2O5 (230.50 ps), strongly indicating that the 2D/2D shell/core interface enables DLWS/Nb2O5 to achieve ultrafast charge transfer from Nb2O5 to atomic double-layer WS2, thus yielding a high photocatalytic H2 evolution rate of 237.6 μmol/h, up to 10.8 times higher than that of pure Nb2O5 nanosheet. This study will open a new window for the development of high-efficient photocatalytic systems through the interface design.
Low-efficiency charge transfer is a critical factor to limit the photocatalytic H2 evolution activity of semiconductor photocatalysts. The interface design is a promising approach to achieve high charge-transfer efficiency for photocatalysts. Herein, a new 2D/2D atomic double-layer WS2/Nb2O5 shell/core photocatalyst (DLWS/Nb2O5) is designed. The atom-resolved HAADF-STEM results unravel the presence of an unusual 2D/2D shell/core interface in DLWS/Nb2O5. Taking advantage of the advanced femtosecond-resolved ultrafast TAS spectra, the average lifetime of charge carriers for DLWS/Nb2O5 (180.97 ps) is considerably shortened as compared to that of Nb2O5 (230.50 ps), strongly indicating that the 2D/2D shell/core interface enables DLWS/Nb2O5 to achieve ultrafast charge transfer from Nb2O5 to atomic double-layer WS2, thus yielding a high photocatalytic H2 evolution rate of 237.6 μmol/h, up to 10.8 times higher than that of pure Nb2O5 nanosheet. This study will open a new window for the development of high-efficient photocatalytic systems through the interface design.
2021, 32(10): 3133-3136
doi: 10.1016/j.cclet.2021.03.059
Abstract:
We have developed a facile strategy to fabricate model multicolor hydrogels via a straightforward mixing process of poly acrylonitrile-grafted methacrylamide (PANMAM), polymethacrylic acid (PMAA) and doped lanthanide (Eu/Tb) and zinc ions to form the interpenetrating dual-polymer gel networks. The hydrogels exhibit excellent tunability of multi-spectrum emission colors (including white light) by simply varying the stoichiometry of metal ions. Furthermore, taking the advantage of different metal ion response mechanisms, we have demonstrated the reversible acidity/alkalinity stimuli-responsive behaviors of white-light-emitting hydrogel (WLE gel). Meanwhile, the unique cross-linked network formed through hydrogen-bonding, metal-ligand coordination and ionic interaction is introduced to achieve favorable mechanical strength of hydrogels. These properties enable the possibility in obtaining fluorescent patterns on hydrogels, which are promising candidate for encrypted information with improved security.
We have developed a facile strategy to fabricate model multicolor hydrogels via a straightforward mixing process of poly acrylonitrile-grafted methacrylamide (PANMAM), polymethacrylic acid (PMAA) and doped lanthanide (Eu/Tb) and zinc ions to form the interpenetrating dual-polymer gel networks. The hydrogels exhibit excellent tunability of multi-spectrum emission colors (including white light) by simply varying the stoichiometry of metal ions. Furthermore, taking the advantage of different metal ion response mechanisms, we have demonstrated the reversible acidity/alkalinity stimuli-responsive behaviors of white-light-emitting hydrogel (WLE gel). Meanwhile, the unique cross-linked network formed through hydrogen-bonding, metal-ligand coordination and ionic interaction is introduced to achieve favorable mechanical strength of hydrogels. These properties enable the possibility in obtaining fluorescent patterns on hydrogels, which are promising candidate for encrypted information with improved security.
2021, 32(10): 3137-3142
doi: 10.1016/j.cclet.2021.02.043
Abstract:
Ammonia (NH3) is considered an attractive candidate as a clean, highly efficient energy carrier. The electrocatalytic nitrogen reduction reaction (NRR) can reduce energy input and carbon footprint; therefore, rational design of effective electrocatalysts is essential for achieving high-efficiency electrocatalytic NH3 synthesis. Herein, we report that the enzymatic mechanism is the more favourable pathway for NRR, due to lower limiting potential (−0.44 V), lower free energy (only 0.02 eV) of the first hydrogenation step (*N–N to *NH–N), and more electron transfer from Fe2B2 to the reaction species. In addition, both vacancies and dopants can be helpful in reducing the reaction energy barrier of the potential-determining step. Therefore, we have demonstrated that Fe2B2 is a potential new candidate for effective NRR and highlighted its potential for applications in electrocatalytic NH3 synthesis.
Ammonia (NH3) is considered an attractive candidate as a clean, highly efficient energy carrier. The electrocatalytic nitrogen reduction reaction (NRR) can reduce energy input and carbon footprint; therefore, rational design of effective electrocatalysts is essential for achieving high-efficiency electrocatalytic NH3 synthesis. Herein, we report that the enzymatic mechanism is the more favourable pathway for NRR, due to lower limiting potential (−0.44 V), lower free energy (only 0.02 eV) of the first hydrogenation step (*N–N to *NH–N), and more electron transfer from Fe2B2 to the reaction species. In addition, both vacancies and dopants can be helpful in reducing the reaction energy barrier of the potential-determining step. Therefore, we have demonstrated that Fe2B2 is a potential new candidate for effective NRR and highlighted its potential for applications in electrocatalytic NH3 synthesis.
2021, 32(10): 3143-3148
doi: 10.1016/j.cclet.2021.02.044
Abstract:
The disinfection of waterborne pathogens from drinking water is extremely important for human health. Although countless efforts have been devoted for drinking water inactivation, challenges still exist in terms of relative high energy consumption and complicated to implement and maintain. Here, silver nanoparticles anchoring wood carbon (Ag NPs/WC) membrane is developed as cost-effective, high flux, scalable filter for highly efficient electric field disinfection of water. Under electric field of 4 V voltage, the designed membrane achieved more than 5 log (99.999%) disinfection performance for different model bacteria, including Escherichia coli (E. coli), Enterococcus faecalis (E. faecalis), Salmonella enterica serovar Typhimirium (S. Typhimurium) and Bacillus subtilis (B. subtilis) with a high flux of 3.8 × 103 L m−2 h−1, extremely low energy consumption of 2 J L−1 m−2 and fantastic durability (7 days). The high disinfection performance of Ag NPs/WC membrane is attributed to the synergistic disinfection of carbon nanofibrils, Ag nanoparticles as well as the low tortuous structure of the channels in wood carbon. The Ag NPs/WC membrane presents a promising strategy for point-of-use drinking water electric field disinfection treatment.
The disinfection of waterborne pathogens from drinking water is extremely important for human health. Although countless efforts have been devoted for drinking water inactivation, challenges still exist in terms of relative high energy consumption and complicated to implement and maintain. Here, silver nanoparticles anchoring wood carbon (Ag NPs/WC) membrane is developed as cost-effective, high flux, scalable filter for highly efficient electric field disinfection of water. Under electric field of 4 V voltage, the designed membrane achieved more than 5 log (99.999%) disinfection performance for different model bacteria, including Escherichia coli (E. coli), Enterococcus faecalis (E. faecalis), Salmonella enterica serovar Typhimirium (S. Typhimurium) and Bacillus subtilis (B. subtilis) with a high flux of 3.8 × 103 L m−2 h−1, extremely low energy consumption of 2 J L−1 m−2 and fantastic durability (7 days). The high disinfection performance of Ag NPs/WC membrane is attributed to the synergistic disinfection of carbon nanofibrils, Ag nanoparticles as well as the low tortuous structure of the channels in wood carbon. The Ag NPs/WC membrane presents a promising strategy for point-of-use drinking water electric field disinfection treatment.
2021, 32(10): 3149-3154
doi: 10.1016/j.cclet.2021.02.046
Abstract:
In this paper, a novel BC3N2 monolayer has been found with a graphene-like structure using the developed particle swarm optimization algorithm in combination with ab initio calculations. The predicted structure meets the thermodynamical, dynamical, and mechanical stability requirements. Interestingly, the BC3N2 plane shows a metallic character. Importantly, BC3N2 has an in-plane stiffness comparable to that of graphene. We have also investigated the adsorption characteristics of CO2 on pristine monolayer and Mo functionalized monolayer using density functional theory. Subsequently, electronic structures of the interacting systems (CO2 molecule and substrates) have been preliminarily explored. The results show that Mo/BC3N2 has a stronger adsorption capacity towards CO2 comparing with the pristine one, which can provide a reference for the further study of the CO2 reduction mechanism on the transition metal-functionalized surface as well as the new catalyst's design.
In this paper, a novel BC3N2 monolayer has been found with a graphene-like structure using the developed particle swarm optimization algorithm in combination with ab initio calculations. The predicted structure meets the thermodynamical, dynamical, and mechanical stability requirements. Interestingly, the BC3N2 plane shows a metallic character. Importantly, BC3N2 has an in-plane stiffness comparable to that of graphene. We have also investigated the adsorption characteristics of CO2 on pristine monolayer and Mo functionalized monolayer using density functional theory. Subsequently, electronic structures of the interacting systems (CO2 molecule and substrates) have been preliminarily explored. The results show that Mo/BC3N2 has a stronger adsorption capacity towards CO2 comparing with the pristine one, which can provide a reference for the further study of the CO2 reduction mechanism on the transition metal-functionalized surface as well as the new catalyst's design.
2021, 32(10): 3155-3158
doi: 10.1016/j.cclet.2021.02.053
Abstract:
Accurate detection of hydrogen sulfide (H2S) is of great significance for environmental monitoring and protection. We propose a colorimetric method for the detection of H2S by the use of mixed-node Cu-Fe metal organic frameworks (Cu-Fe MOFs) as highly efficient mimic enzymes for target-induced deactivation. The Cu-Fe MOFs were synthesized by a simple solvothermal method and could catalyze the H2O2 mediated oxidation of 3, 3′, 5, 5′-tetramethylbenzidine (TMB) to oxTMB with a blue color. The presence of dissolved H2S would deactivate the mimic enzymes, and then the blue color disappeared. The mechanism of the sensor was discussed by steady-state kinetic analysis. The designed assay was highly sensitive for H2S detection with a linear range of 0−80 μmol/L and a detection limit of 1.6 μmol/L. Moreover, some potential substances in the water samples had no interference. This method with the advantages of low cost, high sensitivity, selectivity, and visual readout with the naked eye was successfully applied to the determination of H2S in industrial wastewater samples.
Accurate detection of hydrogen sulfide (H2S) is of great significance for environmental monitoring and protection. We propose a colorimetric method for the detection of H2S by the use of mixed-node Cu-Fe metal organic frameworks (Cu-Fe MOFs) as highly efficient mimic enzymes for target-induced deactivation. The Cu-Fe MOFs were synthesized by a simple solvothermal method and could catalyze the H2O2 mediated oxidation of 3, 3′, 5, 5′-tetramethylbenzidine (TMB) to oxTMB with a blue color. The presence of dissolved H2S would deactivate the mimic enzymes, and then the blue color disappeared. The mechanism of the sensor was discussed by steady-state kinetic analysis. The designed assay was highly sensitive for H2S detection with a linear range of 0−80 μmol/L and a detection limit of 1.6 μmol/L. Moreover, some potential substances in the water samples had no interference. This method with the advantages of low cost, high sensitivity, selectivity, and visual readout with the naked eye was successfully applied to the determination of H2S in industrial wastewater samples.
2021, 32(10): 3159-3163
doi: 10.1016/j.cclet.2021.02.045
Abstract:
Durability is one of the critical issues to restrict the commercialization of proton exchange membrane fuel cells (PEMFCs) for the vehicle application. The practical dynamic operation significantly affects the PEMFCs durability by corroding its key components. In this work, the degradation behavior of a single PEMFC has been investigated under a simulated automotive load-cycling operation, with the aim of revealing the effect of load amplitude (0.8 and 0.2 A/cm2 amplitude for the current density range of 0.1−0.9 and 0.1−0.3 A/cm2, respectively) on its performance degradation. A more severe degradation on the fuel cell performance is observed under a higher load amplitude of 0.8 A/cm2 cycling operation, with ~10.5% decrease of cell voltage at a current density of 1.0 A/cm2. The larger loss of fuel cell performance under the higher load amplitude test is mainly due to the frequent fluctuation of a wider potential cycling. Physicochemical characterizations analyses indicate that the Pt nanoparticles in cathodic catalyst layer grow faster with a higher increase extent of particle size under this circumstance because of their repeated oxidation/reduction and subsequent dissolution/agglomeration process, resulting in the degradation of platinum catalyst and thus the cell performance. Additionally, the detected microstructure change of the cathodic catalyst layer also contributes to the performance failure that causes a distinct increase in mass transfer resistance.
Durability is one of the critical issues to restrict the commercialization of proton exchange membrane fuel cells (PEMFCs) for the vehicle application. The practical dynamic operation significantly affects the PEMFCs durability by corroding its key components. In this work, the degradation behavior of a single PEMFC has been investigated under a simulated automotive load-cycling operation, with the aim of revealing the effect of load amplitude (0.8 and 0.2 A/cm2 amplitude for the current density range of 0.1−0.9 and 0.1−0.3 A/cm2, respectively) on its performance degradation. A more severe degradation on the fuel cell performance is observed under a higher load amplitude of 0.8 A/cm2 cycling operation, with ~10.5% decrease of cell voltage at a current density of 1.0 A/cm2. The larger loss of fuel cell performance under the higher load amplitude test is mainly due to the frequent fluctuation of a wider potential cycling. Physicochemical characterizations analyses indicate that the Pt nanoparticles in cathodic catalyst layer grow faster with a higher increase extent of particle size under this circumstance because of their repeated oxidation/reduction and subsequent dissolution/agglomeration process, resulting in the degradation of platinum catalyst and thus the cell performance. Additionally, the detected microstructure change of the cathodic catalyst layer also contributes to the performance failure that causes a distinct increase in mass transfer resistance.
2021, 32(10): 3164-3168
doi: 10.1016/j.cclet.2021.02.062
Abstract:
Trimethoprim (TMP) is a typical antibiotic to treat infectious disease, which is among the most commonly detected antibacterial agents in natural waters and municipal wastewaters. In the present study, the impacts of dissolved oxygen (DO) on the oxidation efficiency and pathways of TMP by reaction with sulfate radicals (SO4·−) were investigated. Our results revealed that the presence of DO was favourable for TMP degradation. Specifically, TMP would react initially with SO4·− via electron-transfer process to form a carbon-centered radical. In the absence of oxygen, the carbon-centered radical could undergo hydrolysis to produce α-hydroxytrimethoprim (TMP−OH), followed by the further oxidation which generated α-ketotrimethoprim (TMP = O). However, in the presence of oxygen, the carbon-centered radical would alternatively combine with oxygen, leading to a sequential reaction in which peroxyl radical and a tetroxide were formed, and finally generated TMP−OH and TMP=O simultaneously. The proposed pathways were further confirmed by density functional theory (DFT) calculations. The results obtained in this study would emphasize the significance of DO on the oxidation of organic micro-pollutants by SO4·−.
Trimethoprim (TMP) is a typical antibiotic to treat infectious disease, which is among the most commonly detected antibacterial agents in natural waters and municipal wastewaters. In the present study, the impacts of dissolved oxygen (DO) on the oxidation efficiency and pathways of TMP by reaction with sulfate radicals (SO4·−) were investigated. Our results revealed that the presence of DO was favourable for TMP degradation. Specifically, TMP would react initially with SO4·− via electron-transfer process to form a carbon-centered radical. In the absence of oxygen, the carbon-centered radical could undergo hydrolysis to produce α-hydroxytrimethoprim (TMP−OH), followed by the further oxidation which generated α-ketotrimethoprim (TMP = O). However, in the presence of oxygen, the carbon-centered radical would alternatively combine with oxygen, leading to a sequential reaction in which peroxyl radical and a tetroxide were formed, and finally generated TMP−OH and TMP=O simultaneously. The proposed pathways were further confirmed by density functional theory (DFT) calculations. The results obtained in this study would emphasize the significance of DO on the oxidation of organic micro-pollutants by SO4·−.
Preparation of silicon-doped ferrihydrite for adsorption of lead and cadmium: Property and mechanism
2021, 32(10): 3169-3174
doi: 10.1016/j.cclet.2021.03.001
Abstract:
In this study, Si-doped ferrihydrite (Si-Fh) was successfully synthesized by a simple coprecipitation method for removal of heavy metals in water. Subsequently, the physicochemical properties of Si-Fh before and after adsorption were further studied using several techniques. The Si-Fh exhibited good adsorption capacity for heavy metal ions such as Pb(Ⅱ) and Cd(Ⅱ). The maximum adsorption capacities of lead and cadmium are respectively 105.807, 37.986mg/g. The distribution coefficients of the materials for Pb(Ⅱ) and Cd(Ⅱ) also showed a great affinity (under optimal conditions). Moreover, it was found that the adsorption fit well with the Freundlich isotherm and pseudo-second-order kinetic model which means this was a chemical adsorption process. It can be conducted from both characterization and model results that adsorption of Pb(Ⅱ) and Cd(Ⅱ) was mainly through the complexation interaction of abundance oxygen functional groups on the surface of Si-Fh. Overall, the Si-Fh adsorbents with many superiorities have potential for future applications in the removal of Pb(Ⅱ) and Cd(Ⅱ) from wastewater.
In this study, Si-doped ferrihydrite (Si-Fh) was successfully synthesized by a simple coprecipitation method for removal of heavy metals in water. Subsequently, the physicochemical properties of Si-Fh before and after adsorption were further studied using several techniques. The Si-Fh exhibited good adsorption capacity for heavy metal ions such as Pb(Ⅱ) and Cd(Ⅱ). The maximum adsorption capacities of lead and cadmium are respectively 105.807, 37.986mg/g. The distribution coefficients of the materials for Pb(Ⅱ) and Cd(Ⅱ) also showed a great affinity (under optimal conditions). Moreover, it was found that the adsorption fit well with the Freundlich isotherm and pseudo-second-order kinetic model which means this was a chemical adsorption process. It can be conducted from both characterization and model results that adsorption of Pb(Ⅱ) and Cd(Ⅱ) was mainly through the complexation interaction of abundance oxygen functional groups on the surface of Si-Fh. Overall, the Si-Fh adsorbents with many superiorities have potential for future applications in the removal of Pb(Ⅱ) and Cd(Ⅱ) from wastewater.
2021, 32(10): 3175-3179
doi: 10.1016/j.cclet.2021.03.003
Abstract:
In this work, nitric oxide absorption process by using ferrate(Ⅵ)/urea was proposed. The respective influences of the four factors including pH value, ferrate(Ⅵ) concentration, urea concentration, and the temperature and the interactive function of them on nitric oxide absorption were investigated with the response surface methodology (RSM) by central composite design (CCD). The proposed model system showed good consistency with the experiment results, by a correlated coefficient ( R2) of 0.9875. In addition, the interactive influences between any two variables were elaborated through analysis of response surface. The optimal parameters were found at pH of 7.1, reaction temperature of 43.8 ℃, urea concentration of 6.3 wt%, ferrate(Ⅵ) concentration of 4.4 mmol/L for 85.2% NO absorption. Finally, N-containing product analysis shows that nitric oxide was primarily transformed to N2 and NO3−.
In this work, nitric oxide absorption process by using ferrate(Ⅵ)/urea was proposed. The respective influences of the four factors including pH value, ferrate(Ⅵ) concentration, urea concentration, and the temperature and the interactive function of them on nitric oxide absorption were investigated with the response surface methodology (RSM) by central composite design (CCD). The proposed model system showed good consistency with the experiment results, by a correlated coefficient ( R2) of 0.9875. In addition, the interactive influences between any two variables were elaborated through analysis of response surface. The optimal parameters were found at pH of 7.1, reaction temperature of 43.8 ℃, urea concentration of 6.3 wt%, ferrate(Ⅵ) concentration of 4.4 mmol/L for 85.2% NO absorption. Finally, N-containing product analysis shows that nitric oxide was primarily transformed to N2 and NO3−.
2021, 32(10): 3180-3184
doi: 10.1016/j.cclet.2021.03.018
Abstract:
Increasing the charge separation and the utilization efficiency of sunlight are essential factors in a photocatalytic process. In this study, we prepared crystalline N-CQDs@W18O49 heterostructures, through the in situ growth of W18O49 nanocrystals on nitrogen-doped carbon quantum dots (N-CQDs). N-CQDs@W18O49 nanocomposites showed high activity in the photodegradation of ciprofloxacin (CIP) and methyl orange (MO). The photodegradation activity of the optimized N-CQDs@W18O49-5 sample was four times higher than that of W18O49 under ultraviolet-visible (UV–vis) light irradiation. The photodegradation activity of N-CQDs@W18O49-5 sample was two times higher than that of W18O49 under near-infrared (NIR) light irradiation. The enhanced photosensitivity of the nanocomposites was attributed to the promotion of charge separation by N-CQDs and the local surface plasmon resonance (LSPR) effect of W18O49 under NIR light irradiation. This work provides a promising approach for designing and manufacturing photocatalysts with full-spectral responsiveness and improved charge separation.
Increasing the charge separation and the utilization efficiency of sunlight are essential factors in a photocatalytic process. In this study, we prepared crystalline N-CQDs@W18O49 heterostructures, through the in situ growth of W18O49 nanocrystals on nitrogen-doped carbon quantum dots (N-CQDs). N-CQDs@W18O49 nanocomposites showed high activity in the photodegradation of ciprofloxacin (CIP) and methyl orange (MO). The photodegradation activity of the optimized N-CQDs@W18O49-5 sample was four times higher than that of W18O49 under ultraviolet-visible (UV–vis) light irradiation. The photodegradation activity of N-CQDs@W18O49-5 sample was two times higher than that of W18O49 under near-infrared (NIR) light irradiation. The enhanced photosensitivity of the nanocomposites was attributed to the promotion of charge separation by N-CQDs and the local surface plasmon resonance (LSPR) effect of W18O49 under NIR light irradiation. This work provides a promising approach for designing and manufacturing photocatalysts with full-spectral responsiveness and improved charge separation.
2021, 32(10): 3185-3188
doi: 10.1016/j.cclet.2021.03.012
Abstract:
In this research, a novel bird nest-like zinc oxide (BN-ZnO) nanostructures were prepared by a simple solvothermal method. A sensitive electrochemical glucose biosensor was for the first time developed based on the immobilization of glucose oxidase (GOx) on nanostructured BN-ZnO modified electrode. The BN-ZnO nanostructure and the resultant biosensor were characterized by scanning electron microscope, X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, and electrochemical impedance spectroscopy. BN-ZnO nanostructures have large specific surface area and can load large amounts of GOx molecules. Meanwhile, BN-ZnO provides an excellent microenvironment to retain the native bioactivity of enzymes and to promote direct electron transfer between GOx and electrode surface. The proposed biosensor shows a wide linear range of 0.005–1.6 mmol/L, high sensitivity of 15.6 mAL mol−1 cm−2 with a low detection limit of 0.004 mmol/L. The resulting biosensor also shows excellent selectivity, acceptable stability and reproducibility, and can be successfully applied in the detection of glucose in human serum samples at −0.37V.
In this research, a novel bird nest-like zinc oxide (BN-ZnO) nanostructures were prepared by a simple solvothermal method. A sensitive electrochemical glucose biosensor was for the first time developed based on the immobilization of glucose oxidase (GOx) on nanostructured BN-ZnO modified electrode. The BN-ZnO nanostructure and the resultant biosensor were characterized by scanning electron microscope, X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, and electrochemical impedance spectroscopy. BN-ZnO nanostructures have large specific surface area and can load large amounts of GOx molecules. Meanwhile, BN-ZnO provides an excellent microenvironment to retain the native bioactivity of enzymes and to promote direct electron transfer between GOx and electrode surface. The proposed biosensor shows a wide linear range of 0.005–1.6 mmol/L, high sensitivity of 15.6 mAL mol−1 cm−2 with a low detection limit of 0.004 mmol/L. The resulting biosensor also shows excellent selectivity, acceptable stability and reproducibility, and can be successfully applied in the detection of glucose in human serum samples at −0.37V.
2021, 32(10): 3189-3194
doi: 10.1016/j.cclet.2021.03.022
Abstract:
Carbon nanodots (CDs) based fluorescent nanoprobes have recently drawn much attention in chemo-/bio-sensing and bioimaging. However, it is still challenging to integrate the colorimetric and fluorometric dual readouts into a single CD. Herein, novel hybrid CDs (HCDs) are prepared by a simple microwave-assisted reaction of citric acid (CA), branched polyethyleneimine (BPEI) and potassium thiocyanate (KSCN). As-prepared HCDs show extraordinary properties, including excitation-dependent emission, satisfactory fluorescence quantum yield (46.8%), excellent biocompatibility and optical stability. Significantly, the fluorescence intensity at 450 nm exhibits linear correlation over the Fe3+ concentration from 1 μmol/L to 150 μmol/L with a detection limit (LOD) of 52 nmol/L. Meanwhile, the solution color changes from colorless to orange, and the absorbance at 460 nm increased linearly with Fe3+ concentration ranging from 0.02 mmol/L to 5 mmol/L (LOD: 3.4 μmol/L). All the evidence illustrates that the HCDs can be conditioned for specific Fe3+ sensing with colorimetric and fluorometric dual readouts, which has also been verified with paper-based microchips. The possible mechanism is attributed to the specific interactions between surface functional groups on the HCDs and Fe3+. Additionally, the HCDs are successfully applied in sensing Fe3+ in wastewater and living cells, demonstrating its potential applications in future environment monitoring and disease diagnosis.
Carbon nanodots (CDs) based fluorescent nanoprobes have recently drawn much attention in chemo-/bio-sensing and bioimaging. However, it is still challenging to integrate the colorimetric and fluorometric dual readouts into a single CD. Herein, novel hybrid CDs (HCDs) are prepared by a simple microwave-assisted reaction of citric acid (CA), branched polyethyleneimine (BPEI) and potassium thiocyanate (KSCN). As-prepared HCDs show extraordinary properties, including excitation-dependent emission, satisfactory fluorescence quantum yield (46.8%), excellent biocompatibility and optical stability. Significantly, the fluorescence intensity at 450 nm exhibits linear correlation over the Fe3+ concentration from 1 μmol/L to 150 μmol/L with a detection limit (LOD) of 52 nmol/L. Meanwhile, the solution color changes from colorless to orange, and the absorbance at 460 nm increased linearly with Fe3+ concentration ranging from 0.02 mmol/L to 5 mmol/L (LOD: 3.4 μmol/L). All the evidence illustrates that the HCDs can be conditioned for specific Fe3+ sensing with colorimetric and fluorometric dual readouts, which has also been verified with paper-based microchips. The possible mechanism is attributed to the specific interactions between surface functional groups on the HCDs and Fe3+. Additionally, the HCDs are successfully applied in sensing Fe3+ in wastewater and living cells, demonstrating its potential applications in future environment monitoring and disease diagnosis.
2021, 32(10): 3195-3198
doi: 10.1016/j.cclet.2021.03.021
Abstract:
Immobilization of enzymes onto carriers is a rapidly growing research area aimed at increasing the stability, reusability and enzymolysis efficiency of free enzymes. In this work, the role of phase-separation and a pH-responsive "hairy" brush, which greatly affected the topography of porous polymer membrane enzyme reactors (PMER), was explored. The porous polymer membrane was fabricated by phase-separation of poly(styrene- co-maleic anhydride-acrylic acid) and poly(styrene-ethylene glycol). Notably, the topography and pores size of the PMER could be controlled by phase-separation and a pH-responsive "hairy" brush. For evaluating the enzymolysis efficiency of d-amino acid oxidase (DAAO) immobilized carrier (DAAO@PMER), a chiral ligand exchange capillary electrophoresis method was developed with d-methionine as the substrate. The DAAO@PMER showed good reusability and stability after five continuous runs. Notably, comparing with free DAAO in solution, the DAAO@PMER exhibited a 17.7-folds increase in catalytic velocity, which was attributed to its tailorable topography and pH-responsive property. The poly(acrylic acid) moiety of poly(styrene- co-maleic anhydride-acrylic acid) as the pH-responsive "hairy" brush generated topography changing domains upon adjusting the buffer pH, which enable the enzymolysis efficiency of DAAO@PMER to be tuned based upon the well-defined architectures of the PMER. This approach demonstrated that the topographical changes formed by phase-separation and the pH-responsive "hairy" brush indeed made the proposed porous polymer membrane as suitable supports for enzyme immobilization and fitting for enzymolysis applications, achieving high catalytic performance.
Immobilization of enzymes onto carriers is a rapidly growing research area aimed at increasing the stability, reusability and enzymolysis efficiency of free enzymes. In this work, the role of phase-separation and a pH-responsive "hairy" brush, which greatly affected the topography of porous polymer membrane enzyme reactors (PMER), was explored. The porous polymer membrane was fabricated by phase-separation of poly(styrene- co-maleic anhydride-acrylic acid) and poly(styrene-ethylene glycol). Notably, the topography and pores size of the PMER could be controlled by phase-separation and a pH-responsive "hairy" brush. For evaluating the enzymolysis efficiency of d-amino acid oxidase (DAAO) immobilized carrier (DAAO@PMER), a chiral ligand exchange capillary electrophoresis method was developed with d-methionine as the substrate. The DAAO@PMER showed good reusability and stability after five continuous runs. Notably, comparing with free DAAO in solution, the DAAO@PMER exhibited a 17.7-folds increase in catalytic velocity, which was attributed to its tailorable topography and pH-responsive property. The poly(acrylic acid) moiety of poly(styrene- co-maleic anhydride-acrylic acid) as the pH-responsive "hairy" brush generated topography changing domains upon adjusting the buffer pH, which enable the enzymolysis efficiency of DAAO@PMER to be tuned based upon the well-defined architectures of the PMER. This approach demonstrated that the topographical changes formed by phase-separation and the pH-responsive "hairy" brush indeed made the proposed porous polymer membrane as suitable supports for enzyme immobilization and fitting for enzymolysis applications, achieving high catalytic performance.
2021, 32(10): 3199-3201
doi: 10.1016/j.cclet.2021.03.034
Abstract:
A novel flower-shaped zeolitic imidazolate framework (ZIF) doped organic-inorganic hybrid monolithic column (ZIF-HMC) was prepared by a simple sol-gel "one-step" method and utilized for efficient capillary microextraction (CME) of four brominated flame retardants. The prepared monolithic was characterized by Fourier transform infrared, scanning electron microscopy, X-ray photoelectron spectroscopy, energy disperse spectroscopy, and N2 adsorption-desorption. The parameters of CME were optimized by orthogonal array design. Under the optimal conditions, the ZIF-HMC showed excellent extraction efficiency, the limit of detection (LODs) and the limit of quantification (LOQs) were in the range of 0.52~3.1 μg/L and 1.7~10 μg/L, respectively, and the proposed method demonstrated good recovery (88.8%–116.6%) with the RSD less than 13.6% and a reusability of at least 30 times. The ZIF-HMC possessed great potential for separating organic pollutants and the strategy used here could be extended to prepare other derivatized HMC functionalized monoliths.
A novel flower-shaped zeolitic imidazolate framework (ZIF) doped organic-inorganic hybrid monolithic column (ZIF-HMC) was prepared by a simple sol-gel "one-step" method and utilized for efficient capillary microextraction (CME) of four brominated flame retardants. The prepared monolithic was characterized by Fourier transform infrared, scanning electron microscopy, X-ray photoelectron spectroscopy, energy disperse spectroscopy, and N2 adsorption-desorption. The parameters of CME were optimized by orthogonal array design. Under the optimal conditions, the ZIF-HMC showed excellent extraction efficiency, the limit of detection (LODs) and the limit of quantification (LOQs) were in the range of 0.52~3.1 μg/L and 1.7~10 μg/L, respectively, and the proposed method demonstrated good recovery (88.8%–116.6%) with the RSD less than 13.6% and a reusability of at least 30 times. The ZIF-HMC possessed great potential for separating organic pollutants and the strategy used here could be extended to prepare other derivatized HMC functionalized monoliths.
2021, 32(10): 3202-3206
doi: 10.1016/j.cclet.2021.03.038
Abstract:
In order to reduce the greenhouse effect caused by the rapid increase of CO2 concentration in the atmosphere, it is necessary to develop more efficient, controllable, and highly sensitive adsorbing materials. In this study, the adsorption behavior of CO2 on BC3 nanosheets under an external electric field was explored based on density functional theory (DFT). It was found that CO2 experienced a transition from physisorption to chemisorption in the electric field range of 0.0060-0.0065 a.u.. In addition, the adsorption/desorption of CO2 is reversible and can be precisely controlled by switching on/off at the electric field of 0.0065 a.u.. The selective adsorption of CO2/H2/CH4 by BC3 can also be used to realize gas separation and purification under different electric fields. This study highlighted the potential application of BC3 nanosheets as a high-performance, controllable material for CO2 capture, regeneration, and separation in an electric field.
In order to reduce the greenhouse effect caused by the rapid increase of CO2 concentration in the atmosphere, it is necessary to develop more efficient, controllable, and highly sensitive adsorbing materials. In this study, the adsorption behavior of CO2 on BC3 nanosheets under an external electric field was explored based on density functional theory (DFT). It was found that CO2 experienced a transition from physisorption to chemisorption in the electric field range of 0.0060-0.0065 a.u.. In addition, the adsorption/desorption of CO2 is reversible and can be precisely controlled by switching on/off at the electric field of 0.0065 a.u.. The selective adsorption of CO2/H2/CH4 by BC3 can also be used to realize gas separation and purification under different electric fields. This study highlighted the potential application of BC3 nanosheets as a high-performance, controllable material for CO2 capture, regeneration, and separation in an electric field.
2021, 32(10): 3207-3210
doi: 10.1016/j.cclet.2021.03.052
Abstract:
Database-assisted global metabolomics has received growing attention due to its capability for unbiased identification of metabolites in various biological samples. Herein, we established a mass spectrometry (MS)-based database-assisted global metabolomics method and investigated metabolic distance between pleural effusion induced by tuberculosis and malignancy, which are difficult to be distinguished due to their similar clinical symptoms. The present method utilized a liquid chromatography (LC) system coupled with high resolution mass spectrometry (MS) working on full scan and data dependent mode for data acquisition. Unbiased identification of metabolites was performed through mass spectral searching and then confirmed by using authentic standards. As a result, a total of 194 endogenous metabolites were identified and 33 metabolites were found to be differentiated between tuberculous and malignant pleural effusions. These metabolites involved in tryptophan catabolism, bile acid biosynthesis, and β-oxidation of fatty acids, provided non-invasive biomarkers for differentiation of the pleural effusion samples with high sensitivity and specificity.
Database-assisted global metabolomics has received growing attention due to its capability for unbiased identification of metabolites in various biological samples. Herein, we established a mass spectrometry (MS)-based database-assisted global metabolomics method and investigated metabolic distance between pleural effusion induced by tuberculosis and malignancy, which are difficult to be distinguished due to their similar clinical symptoms. The present method utilized a liquid chromatography (LC) system coupled with high resolution mass spectrometry (MS) working on full scan and data dependent mode for data acquisition. Unbiased identification of metabolites was performed through mass spectral searching and then confirmed by using authentic standards. As a result, a total of 194 endogenous metabolites were identified and 33 metabolites were found to be differentiated between tuberculous and malignant pleural effusions. These metabolites involved in tryptophan catabolism, bile acid biosynthesis, and β-oxidation of fatty acids, provided non-invasive biomarkers for differentiation of the pleural effusion samples with high sensitivity and specificity.
2021, 32(10): 3211-3214
doi: 10.1016/j.cclet.2021.03.065
Abstract:
Natural isoquinolinium alkaloids possess a wide range of biological activities. The design and synthesis of mesoionic isoquinoliniums is of great importance. This paper reports the synthesis of unique mesoionic thiazoloisoquinolinium thiolates stabilized by aromatization and 1, 3-dipolarization. Such compounds can be synthesized via the three component [2 + 2 + 1] cycloaddition reaction of isoquinolines with ethyl propionate and elemental sulfur in the absence of any metal catalyst and additives. Importantly, thiazoloisoquinolinium thiolates can be transformed to thioether-containing thiazoloisoquinolinium halides. A selective [4 + 2] cycloaddition can also be used to form S-bridged fused tetracyclic compounds with a thiothiamide ring unit and two quarternary carbon centres. Compound I-1 shows good bioactivity against the chlorophyll of duckweed (Lemna minor) with inhibition rate of 51.5 μg/mL.
Natural isoquinolinium alkaloids possess a wide range of biological activities. The design and synthesis of mesoionic isoquinoliniums is of great importance. This paper reports the synthesis of unique mesoionic thiazoloisoquinolinium thiolates stabilized by aromatization and 1, 3-dipolarization. Such compounds can be synthesized via the three component [2 + 2 + 1] cycloaddition reaction of isoquinolines with ethyl propionate and elemental sulfur in the absence of any metal catalyst and additives. Importantly, thiazoloisoquinolinium thiolates can be transformed to thioether-containing thiazoloisoquinolinium halides. A selective [4 + 2] cycloaddition can also be used to form S-bridged fused tetracyclic compounds with a thiothiamide ring unit and two quarternary carbon centres. Compound I-1 shows good bioactivity against the chlorophyll of duckweed (Lemna minor) with inhibition rate of 51.5 μg/mL.
2021, 32(10): 3215-3220
doi: 10.1016/j.cclet.2021.03.064
Abstract:
Antibiotics such as sulfonamides are widely used in agriculture as growth promoters and medicine in treatment of infectious diseases. However, the release of these antibiotics has caused serious environmental problems. In this paper, photocatalytic oxidation technology was used to degrade sulfadiazine (SDZ), one of the typical sulfonamides antibiotics, in UV illuminated TiO2 suspensions. It was found that TiO2 nanosheets (TiO2-NSs) with exposed (001) facets exhibit much higher photoreactivity towards SDZ degradation compared to TiO2 nanoparticles (TiO2-NPs) with a rate constant increases from 0.017 min-1 to 0.035 min-1, improving by a factor of 2.1. Under the attacking of reactive oxygen species (ROSs) such as superoxide radicals (O2–) and hydroxyl radicals (OH), SDZ was steady degraded on the surface of TiO2-NSs. Based on the identification of the produced intermediates by LC–MS/MS, possible degradation pathways of SDZ, which include desulfonation, oxidation and cleavage, were put forwards. After UV irradiation for 4 h, nearly 90% of the total organic carbon (TOC) can be removed in suspensions of TiO2-NSs, indicating the mineralization of SDZ. TiO2-NSs also exhibits excellent stability in photocatalytic degradation of SDZ in wide range of pH. Even after recycling used for 7 times, more than 91.3% of the SDZ can be efficiently removed, indicating that they are promising to be practically used in treatment of wastewater containing antibiotics.
Antibiotics such as sulfonamides are widely used in agriculture as growth promoters and medicine in treatment of infectious diseases. However, the release of these antibiotics has caused serious environmental problems. In this paper, photocatalytic oxidation technology was used to degrade sulfadiazine (SDZ), one of the typical sulfonamides antibiotics, in UV illuminated TiO2 suspensions. It was found that TiO2 nanosheets (TiO2-NSs) with exposed (001) facets exhibit much higher photoreactivity towards SDZ degradation compared to TiO2 nanoparticles (TiO2-NPs) with a rate constant increases from 0.017 min-1 to 0.035 min-1, improving by a factor of 2.1. Under the attacking of reactive oxygen species (ROSs) such as superoxide radicals (O2–) and hydroxyl radicals (OH), SDZ was steady degraded on the surface of TiO2-NSs. Based on the identification of the produced intermediates by LC–MS/MS, possible degradation pathways of SDZ, which include desulfonation, oxidation and cleavage, were put forwards. After UV irradiation for 4 h, nearly 90% of the total organic carbon (TOC) can be removed in suspensions of TiO2-NSs, indicating the mineralization of SDZ. TiO2-NSs also exhibits excellent stability in photocatalytic degradation of SDZ in wide range of pH. Even after recycling used for 7 times, more than 91.3% of the SDZ can be efficiently removed, indicating that they are promising to be practically used in treatment of wastewater containing antibiotics.
2021, 32(10): 3221-3225
doi: 10.1016/j.cclet.2021.03.072
Abstract:
Electrochemical heterogeneous catalytic ozonation (E-catazone) is a promising and advanced oxidation technology that uses a titanium dioxide nanoflower (TiO2-NF)-coated porous Ti gas diffuser as an anode material. Our previous study has highlighted that the importance of the TiO2-NF coating layer in enhancing OH production and rapidly degrading O3-resistant drugs. It is well known that the properties of TiO2-NF are closely related to its sintering temperature. However, to date, related research has not been conducted in E-catazone systems. Thus, this study evaluated the effect of the sintering temperature on the degradation of the O3-resistant drug para-chlorobenzoic acid (p-CBA) using both experimental and kinetic modeling and revealed its influence mechanism. The results indicated that the TiO2-NF sintering temperature could influence p-CBA degradation and OH production. TiO2-NF prepared at 450 ℃ showcased the highest p-CBA removal efficiency (98.5% in 5 min) at a rate of 0.82 min-1, and an OH exposure of 8.41 × 10-10molL-1s. Kinetic modeling results and interface characterization data revealed that the sintering temperature could alter the TiO2 crystallized phase and the content of surface-adsorbed oxygen, thus affecting the two key limiting reactions in the E-catazone process. That is, ≡TiO2 surface reacted with H2O to form TiO2-(OH)2, which then heterogeneously catalyzed O3 to form OH. Consequently, E-catazone with a TiO2-NF anode prepared at 450 ℃ generated the highest surface reaction rate (5.00 × 10-1 s-1 and 4.00 × 10-3 L mol-1 s-1, respectively), owing to its higher anatase content and adsorbed oxygen. Thus, a rapid O3-TiO2 reaction was achieved, resulting in an enhanced OH formation and a highly effective p-CBA degradation. Overall, this study provides novel baseline data to improve the application of E-catazone technology.
Electrochemical heterogeneous catalytic ozonation (E-catazone) is a promising and advanced oxidation technology that uses a titanium dioxide nanoflower (TiO2-NF)-coated porous Ti gas diffuser as an anode material. Our previous study has highlighted that the importance of the TiO2-NF coating layer in enhancing OH production and rapidly degrading O3-resistant drugs. It is well known that the properties of TiO2-NF are closely related to its sintering temperature. However, to date, related research has not been conducted in E-catazone systems. Thus, this study evaluated the effect of the sintering temperature on the degradation of the O3-resistant drug para-chlorobenzoic acid (p-CBA) using both experimental and kinetic modeling and revealed its influence mechanism. The results indicated that the TiO2-NF sintering temperature could influence p-CBA degradation and OH production. TiO2-NF prepared at 450 ℃ showcased the highest p-CBA removal efficiency (98.5% in 5 min) at a rate of 0.82 min-1, and an OH exposure of 8.41 × 10-10molL-1s. Kinetic modeling results and interface characterization data revealed that the sintering temperature could alter the TiO2 crystallized phase and the content of surface-adsorbed oxygen, thus affecting the two key limiting reactions in the E-catazone process. That is, ≡TiO2 surface reacted with H2O to form TiO2-(OH)2, which then heterogeneously catalyzed O3 to form OH. Consequently, E-catazone with a TiO2-NF anode prepared at 450 ℃ generated the highest surface reaction rate (5.00 × 10-1 s-1 and 4.00 × 10-3 L mol-1 s-1, respectively), owing to its higher anatase content and adsorbed oxygen. Thus, a rapid O3-TiO2 reaction was achieved, resulting in an enhanced OH formation and a highly effective p-CBA degradation. Overall, this study provides novel baseline data to improve the application of E-catazone technology.
2021, 32(10): 3226-3230
doi: 10.1016/j.cclet.2021.04.003
Abstract:
Low dimension nano photocatalysts show great potential in the field of treating contaminated water for their large surface area and size effect. In this study, a 0D/1D AgI/MoO3 Z-scheme photocatalyst with striking photocatalytic performance was constructed successfully. The one-dimensional MoO3 nanobelts were prepared by a simple hydrothermal method, and then it was modified by AgI nanoparticles in a handy deposition approach. When choosing sulfamethoxazole (SMZ) as the target contaminant, the rate constant value of the optimal 0D/1D AgI/MoO3 composite could hit up to 0.13 min-1, which is nearly 22.4 times and 32.5 times as that of pure MoO3 (0.0058 min-1) and AgI (0.0040 min-1), respectively. A series of detailed characterizations give evidences that the charge transfer in the composite followed Z scheme mechanism. Therefore, efficient separation/transfer and the remained high redox activity of photogenerated carriers played a vital role in the sharply enhanced photocatalytic properties. The possible degradation pathways of SMZ were proposed based on the intermediates detected by high-performance liquid chromatography-mass spectrometry (HPLC-MS). Meanwhile, the magnificent cyclic stability makes the material a promising material in the practical application.
Low dimension nano photocatalysts show great potential in the field of treating contaminated water for their large surface area and size effect. In this study, a 0D/1D AgI/MoO3 Z-scheme photocatalyst with striking photocatalytic performance was constructed successfully. The one-dimensional MoO3 nanobelts were prepared by a simple hydrothermal method, and then it was modified by AgI nanoparticles in a handy deposition approach. When choosing sulfamethoxazole (SMZ) as the target contaminant, the rate constant value of the optimal 0D/1D AgI/MoO3 composite could hit up to 0.13 min-1, which is nearly 22.4 times and 32.5 times as that of pure MoO3 (0.0058 min-1) and AgI (0.0040 min-1), respectively. A series of detailed characterizations give evidences that the charge transfer in the composite followed Z scheme mechanism. Therefore, efficient separation/transfer and the remained high redox activity of photogenerated carriers played a vital role in the sharply enhanced photocatalytic properties. The possible degradation pathways of SMZ were proposed based on the intermediates detected by high-performance liquid chromatography-mass spectrometry (HPLC-MS). Meanwhile, the magnificent cyclic stability makes the material a promising material in the practical application.
2021, 32(10): 3231-3236
doi: 10.1016/j.cclet.2021.03.086
Abstract:
A magnesium doped ferrihydrite-humic acid coprecipitation (Mg-doped Fh-HA) was synthesized by coprecipitation method. The removal of heavy metals such as Pb(Ⅱ) and Cd(Ⅱ) was assessed. The isotherms and kinetic studies indicated that the Mg-doped Fh-HA exhibited a remarkable Pb(Ⅱ) and Cd(Ⅱ) sorption capacity (maximum 120.43 mg/g and 27.7 mg/g, respectively.) in aqueous solution. The sorption of Pb(Ⅱ) and Cd(Ⅱ) onto best fitted pseudo-second-order kinetic equation and Langmuir model. The adsorption mechanism of Mg-doped Fh-HA on Pb(Ⅱ) and Cd(Ⅱ) involves surface adsorption, surface complexation and surface functional groups (such as carboxyl group, hydroxyl group). In addition, ion-exchange and precipitation cannot be ignored. The Mg-doped Fh-HA is a low-cost and high-performance adsorption material and has a wide range of application prospects.
A magnesium doped ferrihydrite-humic acid coprecipitation (Mg-doped Fh-HA) was synthesized by coprecipitation method. The removal of heavy metals such as Pb(Ⅱ) and Cd(Ⅱ) was assessed. The isotherms and kinetic studies indicated that the Mg-doped Fh-HA exhibited a remarkable Pb(Ⅱ) and Cd(Ⅱ) sorption capacity (maximum 120.43 mg/g and 27.7 mg/g, respectively.) in aqueous solution. The sorption of Pb(Ⅱ) and Cd(Ⅱ) onto best fitted pseudo-second-order kinetic equation and Langmuir model. The adsorption mechanism of Mg-doped Fh-HA on Pb(Ⅱ) and Cd(Ⅱ) involves surface adsorption, surface complexation and surface functional groups (such as carboxyl group, hydroxyl group). In addition, ion-exchange and precipitation cannot be ignored. The Mg-doped Fh-HA is a low-cost and high-performance adsorption material and has a wide range of application prospects.
2021, 32(10): 3237-3240
doi: 10.1016/j.cclet.2021.04.031
Abstract:
Polyoxyethylene glycerol ricinoleate (PGR) serves as a solubilizer/emulsifier that is commonly used in pharmaceutical formulations despite being associated with severe anaphylactoid hypersensitivity reactions. Cremophor EL® (CrEL) is the most representative PGR produced from reacting ethylene oxide with castor oil. To help clarify the cause of side effects and potentially improve the safety of PGR-based drug delivery vehicle, we have developed separate but related analytical methods for the quantitation of CrEL and its main metabolites, glycerol ethoxylate (GE) and ricinoleic acid (RA). Since CrEL and GE are highly disperse mixtures of polymers that are not amenable to analysis by conventional liquid chromatography-tandem mass spectrometry (LC-MS/MS), we used liquid chromatography-triple-quadrupole-time-of-flight mass spectrometry (LC-Q-TOF MS) combined with product ion data acquisition by MSALL and sequential window acquisition of all theoretical fragments mass spectrometry (SWATH MS), respectively to perform the analysis. In contrast, RA is a single molecular entity that could be readily analyzed using conventional LC-HR MS/MS. Selection of specific fragment ions for CrEL, GE, RA and their internal standards enabled a precise quantitation of such a complex analytes system in rat plasma after a single and simple sample preparation method. Assay validation indicated linearity for CrEL, GE and RA over the concentration ranges 0.2~20.0 μg/mL, 0.1~10.0 μg/mL and 0.1~20.0 μg/mL, respectively with satisfactory results for other validation parameters. A subsequent pharmacokinetic study involving single intravenous 200 mg/kg injections of CrEL to rats showed the methods enable comprehensive and high throughput quantitation of CrEL and its metabolites in a biological matrix. Our combination of assays provides effective application in investigating the cause of the hypersensitivity reaction of PGR and potentially to improve its safety for using as a vehicle in drug formulations.
Polyoxyethylene glycerol ricinoleate (PGR) serves as a solubilizer/emulsifier that is commonly used in pharmaceutical formulations despite being associated with severe anaphylactoid hypersensitivity reactions. Cremophor EL® (CrEL) is the most representative PGR produced from reacting ethylene oxide with castor oil. To help clarify the cause of side effects and potentially improve the safety of PGR-based drug delivery vehicle, we have developed separate but related analytical methods for the quantitation of CrEL and its main metabolites, glycerol ethoxylate (GE) and ricinoleic acid (RA). Since CrEL and GE are highly disperse mixtures of polymers that are not amenable to analysis by conventional liquid chromatography-tandem mass spectrometry (LC-MS/MS), we used liquid chromatography-triple-quadrupole-time-of-flight mass spectrometry (LC-Q-TOF MS) combined with product ion data acquisition by MSALL and sequential window acquisition of all theoretical fragments mass spectrometry (SWATH MS), respectively to perform the analysis. In contrast, RA is a single molecular entity that could be readily analyzed using conventional LC-HR MS/MS. Selection of specific fragment ions for CrEL, GE, RA and their internal standards enabled a precise quantitation of such a complex analytes system in rat plasma after a single and simple sample preparation method. Assay validation indicated linearity for CrEL, GE and RA over the concentration ranges 0.2~20.0 μg/mL, 0.1~10.0 μg/mL and 0.1~20.0 μg/mL, respectively with satisfactory results for other validation parameters. A subsequent pharmacokinetic study involving single intravenous 200 mg/kg injections of CrEL to rats showed the methods enable comprehensive and high throughput quantitation of CrEL and its metabolites in a biological matrix. Our combination of assays provides effective application in investigating the cause of the hypersensitivity reaction of PGR and potentially to improve its safety for using as a vehicle in drug formulations.
2021, 32(10): 3241-3244
doi: 10.1016/j.cclet.2021.04.051
Abstract:
Water electrolysis is considered to be an effective and promising technology to make high-purity H2, however, the relationship between anion species and catalytic performance of electrocatalysts is still not completely clear. Herein, we report an anion engineering strategy to tune electrocatalytic water oxidation activity for Co-based materials. Novel hierarchical Co-based oxide/selenide/phosphide (Co-A, A = O, Se, P) hexagrams have been chosen as model materials. Electrochemical results and theoretical calculations reveal that the electron configuration, the electrical conductivity, and the oxidation potential of Co element in Co-A hexagrams could be moderated by the substitution of P atoms, which leads to the superior OER performance. Particularly, Co-P hexagram displays a low overpotential (η = 269 mV) at j = 10 mA/cm2 for the oxygen evolution reaction (OER) compared to Co-O hexagram (η = 399 mV) and Co-Se hexagram (η = 347 mV). This work is of great importance in understanding coordination atoms (O, Se and P) induced electrocatalytic properties of hierarchical Co-based materials.
Water electrolysis is considered to be an effective and promising technology to make high-purity H2, however, the relationship between anion species and catalytic performance of electrocatalysts is still not completely clear. Herein, we report an anion engineering strategy to tune electrocatalytic water oxidation activity for Co-based materials. Novel hierarchical Co-based oxide/selenide/phosphide (Co-A, A = O, Se, P) hexagrams have been chosen as model materials. Electrochemical results and theoretical calculations reveal that the electron configuration, the electrical conductivity, and the oxidation potential of Co element in Co-A hexagrams could be moderated by the substitution of P atoms, which leads to the superior OER performance. Particularly, Co-P hexagram displays a low overpotential (η = 269 mV) at j = 10 mA/cm2 for the oxygen evolution reaction (OER) compared to Co-O hexagram (η = 399 mV) and Co-Se hexagram (η = 347 mV). This work is of great importance in understanding coordination atoms (O, Se and P) induced electrocatalytic properties of hierarchical Co-based materials.
2021, 32(10): 3245-3251
doi: 10.1016/j.cclet.2021.03.019
Abstract:
Although magnetic stirring is frequently used to enhance the kinetics for adsorption, chemical and biochemical reactions, the introduction of stirrers inevitably leads to the adsorption of analytes and thus interferes with the efficiency of the chemical process or reaction. In this work, magnetic Fe3O4 nanorods with tunable length-to-diameter ratio were synthesized via a hydrothermal method and used as templates for the in-situ depositing of MIL-100(Fe) and gold nanoparticles. Such nanorod-based material can not only function as an adsorbent, nanozyme, and a heterogeneous catalyst for corresponding applications but also serve as a magnetic nanostirrer to enhance kinetics. As a proof-of-concept, the capture of bacteria pathogen, mimic-peroxidase-based colorimetric detection of hydrogen peroxide, and the catalytic reduction of selected organic pollutants were conducted using the as-synthesized Fe3O4@MIL-100(Fe)-Au nanostirrer with and without magnetic field. The results show that the rates of bacteria capture, mimetic enzyme reaction and catalysis were tremendously expedited. We believe this magnetic field-assisted approach holds great promise for future applications, because, not only does it eliminate the use of external magnetic stirrers and thereby decrease the risk of foreign pollution but also, is adaptable for nanoscale reaction systems where conventional stirring is not applicable due to size limitations.
Although magnetic stirring is frequently used to enhance the kinetics for adsorption, chemical and biochemical reactions, the introduction of stirrers inevitably leads to the adsorption of analytes and thus interferes with the efficiency of the chemical process or reaction. In this work, magnetic Fe3O4 nanorods with tunable length-to-diameter ratio were synthesized via a hydrothermal method and used as templates for the in-situ depositing of MIL-100(Fe) and gold nanoparticles. Such nanorod-based material can not only function as an adsorbent, nanozyme, and a heterogeneous catalyst for corresponding applications but also serve as a magnetic nanostirrer to enhance kinetics. As a proof-of-concept, the capture of bacteria pathogen, mimic-peroxidase-based colorimetric detection of hydrogen peroxide, and the catalytic reduction of selected organic pollutants were conducted using the as-synthesized Fe3O4@MIL-100(Fe)-Au nanostirrer with and without magnetic field. The results show that the rates of bacteria capture, mimetic enzyme reaction and catalysis were tremendously expedited. We believe this magnetic field-assisted approach holds great promise for future applications, because, not only does it eliminate the use of external magnetic stirrers and thereby decrease the risk of foreign pollution but also, is adaptable for nanoscale reaction systems where conventional stirring is not applicable due to size limitations.
2021, 32(10): 3252-3256
doi: 10.1016/j.cclet.2021.02.036
Abstract:
Covalent DNA–protein cross-links are toxic DNA lesions that interfere with essential biological processes, which can cause serious biological consequences, such as genomic instability and protein misexpression. 5-Formyluracil (5fU) as an important modification in DNA, which is mainly from oxidative damage, exists in a variety of cells and tissues. We have reported that 5fU mediated DNA–protein conjugates could exist in human cells [Zhou et al. CCS Chem. 2 (2020) 54-63]. We now aimed to explore its potential biological effects in vitro and in vivo. In this paper, we firstly reported that 5fU intermediated DNA–peptide or DNA–protein conjugates (both were called DPCs) could inhibit different polymerases bypass or cause mutations. Then we further investigated the functional impacts caused by 5fU-mediated DPCs, which appeared in different gene expression components [in the promoter sequence or 5′-untranslated regions (UTR)]. These results together may contribute to a broader understanding of DNA–protein interactions as well as the biological functions associated with 5fU.
Covalent DNA–protein cross-links are toxic DNA lesions that interfere with essential biological processes, which can cause serious biological consequences, such as genomic instability and protein misexpression. 5-Formyluracil (5fU) as an important modification in DNA, which is mainly from oxidative damage, exists in a variety of cells and tissues. We have reported that 5fU mediated DNA–protein conjugates could exist in human cells [Zhou et al. CCS Chem. 2 (2020) 54-63]. We now aimed to explore its potential biological effects in vitro and in vivo. In this paper, we firstly reported that 5fU intermediated DNA–peptide or DNA–protein conjugates (both were called DPCs) could inhibit different polymerases bypass or cause mutations. Then we further investigated the functional impacts caused by 5fU-mediated DPCs, which appeared in different gene expression components [in the promoter sequence or 5′-untranslated regions (UTR)]. These results together may contribute to a broader understanding of DNA–protein interactions as well as the biological functions associated with 5fU.
2021, 32(10): 3257-3260
doi: 10.1016/j.cclet.2021.03.004
Abstract:
Three phthalide-derived analogues, oxaspiroangelioic acids A–C (1–3), were isolated as minor components of an aqueous extract of the Angelica sinensis root heads (guitou). Oxaspiroangelioic acids A and B were racemates separated into enantiomers by chiral HPLC. Their structures including absolute configurations were determined by spectroscopic data analysis, single crystal X-ray diffraction, exciton chirality method and electronic circular dichroism (ECD) calculation. These compounds share an undescribed carbon skeleton, for which biosynthetic pathways are proposed. Compound 1 and its enantiomers showed almost identical activity inhibiting Tandem of P domains in a weak inwardly rectifying K+ channel 1 (TREK-1).
Three phthalide-derived analogues, oxaspiroangelioic acids A–C (1–3), were isolated as minor components of an aqueous extract of the Angelica sinensis root heads (guitou). Oxaspiroangelioic acids A and B were racemates separated into enantiomers by chiral HPLC. Their structures including absolute configurations were determined by spectroscopic data analysis, single crystal X-ray diffraction, exciton chirality method and electronic circular dichroism (ECD) calculation. These compounds share an undescribed carbon skeleton, for which biosynthetic pathways are proposed. Compound 1 and its enantiomers showed almost identical activity inhibiting Tandem of P domains in a weak inwardly rectifying K+ channel 1 (TREK-1).
2021, 32(10): 3261-3263
doi: 10.1016/j.cclet.2021.05.015
Abstract:
The composite photoanodes composed by cobalt phosphate catalyst (Co−Pi) modified semiconductor have been widely used for solar water splitting, but the improvement mechanism has not been experimentally confirmed. Here we use transient photoelectrochemical measurements and impedance spectroscopy to investigate the effect of Co−Pi catalyst on hematite nanowire photoanode. It is found that under illumination the Co−Pi catalyst can efficiently promote the transfer of photo-generated holes to the Co−Pi layer by increasing the electrical conductivity of the composite structure under a low potential. The Co−Pi catalyst can recombine with photo-generated electrons to reduce the surface recombination efficiency of photo-generated holes and electrons under a high potential. These results provide important new understanding of the performance improvement mechanism for the Co−Pi-modified semiconductor nanowire composite photoanodes.
The composite photoanodes composed by cobalt phosphate catalyst (Co−Pi) modified semiconductor have been widely used for solar water splitting, but the improvement mechanism has not been experimentally confirmed. Here we use transient photoelectrochemical measurements and impedance spectroscopy to investigate the effect of Co−Pi catalyst on hematite nanowire photoanode. It is found that under illumination the Co−Pi catalyst can efficiently promote the transfer of photo-generated holes to the Co−Pi layer by increasing the electrical conductivity of the composite structure under a low potential. The Co−Pi catalyst can recombine with photo-generated electrons to reduce the surface recombination efficiency of photo-generated holes and electrons under a high potential. These results provide important new understanding of the performance improvement mechanism for the Co−Pi-modified semiconductor nanowire composite photoanodes.
