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2020 Volume 78 Issue 11
2020, 78(11): 1139-1149
doi: 10.6023/A20060267
Abstract:
Boron nitride nanosheets (BNNSs), also known as "white graphene", is an important nanofiller with excellent mechanical properties, thermal conductivity, abrasion resistance, barrier properties, and hydrophobicity. It is also a new type of excellent performance insulation materials. It is widely used in heavy-duty anti-corrosion coatings, lubricants, sensors and other fields. Based on the huge application prospects of BNNSs in the field of metal corrosion protection, this article systematically summarizes the preparation and surface functionalization of BNNSs, boron nitride thin film protective coatings, BNNSs/organic protective coatings, BNNSs-inorganic materials/organic protective coatings, and focuses on the detailed analysis and existing problems of BNNSs uniformly dispersed in organic coatings and used for metal corrosion protection. The future development of BNNSs-based anticorrosive coatings is prospected.
Boron nitride nanosheets (BNNSs), also known as "white graphene", is an important nanofiller with excellent mechanical properties, thermal conductivity, abrasion resistance, barrier properties, and hydrophobicity. It is also a new type of excellent performance insulation materials. It is widely used in heavy-duty anti-corrosion coatings, lubricants, sensors and other fields. Based on the huge application prospects of BNNSs in the field of metal corrosion protection, this article systematically summarizes the preparation and surface functionalization of BNNSs, boron nitride thin film protective coatings, BNNSs/organic protective coatings, BNNSs-inorganic materials/organic protective coatings, and focuses on the detailed analysis and existing problems of BNNSs uniformly dispersed in organic coatings and used for metal corrosion protection. The future development of BNNSs-based anticorrosive coatings is prospected.
2020, 78(11): 1150-1163
doi: 10.6023/A20060253
Abstract:
The origin of life attracts more and more attentions of researchers. Synthetic biologists are devoting to construct a simple and rational system which can exist in primitive earth. Coacervate is a phase separation system which is formed by the interactions of polyelectrolyte. It's a rational protocell model. So far, coacervate has been found to present as membraneless organelles in natural cells. Therefore, the construction of coacervate as artificial organelles is emerging. The formation mechanism, characteristics and categories of coacervate are reviewed in this paper. Additionally, the applications of coacervate as protocell and artificial organelles are summarized. The existing scientific problems and the future development directions are provided at the end of this paper.
The origin of life attracts more and more attentions of researchers. Synthetic biologists are devoting to construct a simple and rational system which can exist in primitive earth. Coacervate is a phase separation system which is formed by the interactions of polyelectrolyte. It's a rational protocell model. So far, coacervate has been found to present as membraneless organelles in natural cells. Therefore, the construction of coacervate as artificial organelles is emerging. The formation mechanism, characteristics and categories of coacervate are reviewed in this paper. Additionally, the applications of coacervate as protocell and artificial organelles are summarized. The existing scientific problems and the future development directions are provided at the end of this paper.
2020, 78(11): 1164-1176
doi: 10.6023/A20100486
Abstract:
Lanthanide elements show great advantages in luminescence materials and are increasingly applied in the design of advanced functional luminescence materials due to their excellent luminescence characteristics, such as long-lived excited states, narrow emission bandwidths and large Stokes shift. Cyclodextrin, as the second generation supramolecular host molecule, is easy to be functionalized and specifically binds the luminescent guests, so it is widely used to construct supramolecular systems such as luminescent materials and fluorescence sensing probes. In this paper, based on the construction of supramolecular assemblies of lanthanide/cyclodextrin, the author reviews the recent research progress of different lanthanide/cyclodextrin luminescent materials, which will provide reference for the development of new multifunctional lanthanide luminescent materials. Finally, the scientific problems encountered by lanthanide luminescent materials are put forward, and the development direction of lanthanide/cylodextrin luminescent materials is prospected.
Lanthanide elements show great advantages in luminescence materials and are increasingly applied in the design of advanced functional luminescence materials due to their excellent luminescence characteristics, such as long-lived excited states, narrow emission bandwidths and large Stokes shift. Cyclodextrin, as the second generation supramolecular host molecule, is easy to be functionalized and specifically binds the luminescent guests, so it is widely used to construct supramolecular systems such as luminescent materials and fluorescence sensing probes. In this paper, based on the construction of supramolecular assemblies of lanthanide/cyclodextrin, the author reviews the recent research progress of different lanthanide/cyclodextrin luminescent materials, which will provide reference for the development of new multifunctional lanthanide luminescent materials. Finally, the scientific problems encountered by lanthanide luminescent materials are put forward, and the development direction of lanthanide/cylodextrin luminescent materials is prospected.
2020, 78(11): 1177-1184
doi: 10.6023/A20060252
Abstract:
The levels of some biomolecules and ions in the body are usually related to the structural and functional changes of cells, tissues, organs, etc., which directly affect the prevention, diagnosis, and treatment of diseases. Therefore, in vivo bioassays of these substances are of great significance in medical and healthcare fields. The nano fluorescent probes consisted of rare earth nano materials have advantages of high sensitivity, simplicity, efficiency, and strong anti-interference ability, thus showing great potential in bioassays. The functionalization of aptamers on rare earth nanomaterials can further provide better specific recognition ability and biocompatibility for nano fluorescent probes, thereby enhancing their bioassays ability in complex samples. In this paper, the research progress of aptamer-functionalized rare earth nanomaterials as nano fluorescent probes in the field of bioassays is reviewed, and the main types, properties, detection mechanisms and detection substances are briefly introduced.
The levels of some biomolecules and ions in the body are usually related to the structural and functional changes of cells, tissues, organs, etc., which directly affect the prevention, diagnosis, and treatment of diseases. Therefore, in vivo bioassays of these substances are of great significance in medical and healthcare fields. The nano fluorescent probes consisted of rare earth nano materials have advantages of high sensitivity, simplicity, efficiency, and strong anti-interference ability, thus showing great potential in bioassays. The functionalization of aptamers on rare earth nanomaterials can further provide better specific recognition ability and biocompatibility for nano fluorescent probes, thereby enhancing their bioassays ability in complex samples. In this paper, the research progress of aptamer-functionalized rare earth nanomaterials as nano fluorescent probes in the field of bioassays is reviewed, and the main types, properties, detection mechanisms and detection substances are briefly introduced.
2020, 78(11): 1185-1199
doi: 10.6023/A20060265
Abstract:
Electrocatalytic biomass conversion, which utilizing the electrical energy generated by intermittent energy, drive biomass into high value-added organic chemicals, and usually can be coupled with water splitting for the production of high-purity hydrogen. It has the potential to significantly decrease fossil fuel consumption, optimize energy structure and solve environmental issues. However, because biomass possess multiple groups and its conversion involves multiple electrons, electrocatalytic biomass conversion suffer from low conversion efficiency, bad selectivity and poor stability. Surface and interface chemistry engineering, such as regulating intrinsic structure, generating vacancies, introducing heteroatom, and constructing synergistic interface, can design and modify two-dimensional electrocatalysts to optimize their electronic structure and geometric structure, and effectively improve the electrocatalytic efficiency, selectivity and stability. This review provides an overview of recent advances about the role of surface and interface chemistry played on electrocatalytic biomass conversion of two-dimensional materials. In addition, the authors also give some perspectives on the challenges and prospects in this field.
Electrocatalytic biomass conversion, which utilizing the electrical energy generated by intermittent energy, drive biomass into high value-added organic chemicals, and usually can be coupled with water splitting for the production of high-purity hydrogen. It has the potential to significantly decrease fossil fuel consumption, optimize energy structure and solve environmental issues. However, because biomass possess multiple groups and its conversion involves multiple electrons, electrocatalytic biomass conversion suffer from low conversion efficiency, bad selectivity and poor stability. Surface and interface chemistry engineering, such as regulating intrinsic structure, generating vacancies, introducing heteroatom, and constructing synergistic interface, can design and modify two-dimensional electrocatalysts to optimize their electronic structure and geometric structure, and effectively improve the electrocatalytic efficiency, selectivity and stability. This review provides an overview of recent advances about the role of surface and interface chemistry played on electrocatalytic biomass conversion of two-dimensional materials. In addition, the authors also give some perspectives on the challenges and prospects in this field.
2020, 78(11): 1200-1212
doi: 10.6023/A20060215
Abstract:
Hollow nanostructures garner tremendous interest in the area of energy conversion and storage, owning to its large surface area, facilitated transport path and good buffering capability. In this paper, we summarize the recent research on hollow nanostructures with controllable structure and morphology for surface/interface chemical energy storage. First, we introduce the charge storage mechanism and challenges of surface/interface chemical energy storage, mainly including supercapacitor. Subsequently, we discuss the influence of structure parameters of hollow nanostructures on the performance of surface/interface chemical energy storage device in detail. Afterwards, we systematically outline the recent applications of hollow nanostructures as electrode materials for supercapacitors. By adopting hollow nanostructures, the specific capacitance, cycle stability and rate capability of supercapacitors can be greatly improved. Finally, the emergent challenges and future development directions in hollow nanostructures for surface/interface chemical energy storage are provided.
Hollow nanostructures garner tremendous interest in the area of energy conversion and storage, owning to its large surface area, facilitated transport path and good buffering capability. In this paper, we summarize the recent research on hollow nanostructures with controllable structure and morphology for surface/interface chemical energy storage. First, we introduce the charge storage mechanism and challenges of surface/interface chemical energy storage, mainly including supercapacitor. Subsequently, we discuss the influence of structure parameters of hollow nanostructures on the performance of surface/interface chemical energy storage device in detail. Afterwards, we systematically outline the recent applications of hollow nanostructures as electrode materials for supercapacitors. By adopting hollow nanostructures, the specific capacitance, cycle stability and rate capability of supercapacitors can be greatly improved. Finally, the emergent challenges and future development directions in hollow nanostructures for surface/interface chemical energy storage are provided.
2020, 78(11): 1213-1222
doi: 10.6023/A20060259
Abstract:
The detection of tumor markers plays an important role in the screening, early diagnosis and treatment of high-risk cancer patients. Prostatic cancer is one of the most common malignancies of the male genitourinary system, and has an increasing trend in recent years. Its morbidity is generally influenced by region and ethnicity. The common clinical markers of prostate cancer include prostate-specific antigen (PSA), prostate-specific membrane antigen (PSMA), alpha-formyl kievase A mesozyme (AMACR, P504S), prostate-acid phosphatase (PAP), and calcium phosphatidyl binding protein 3 (ANXA3). Most of these markers are composed of proteins or enzymes, which are produced by normal or cancerous prostate cells. Of these, prostate-specific antigen (PSA) and prostate-acid phosphatase (PAP) are considered to be the most meaningful markers of the prostatic cancer. Detection of PSA is widely used in the early detection and monitoring of prostate cancer patients, while analysis of PAP is often used to detect advanced prostate cancer metastases and evaluate the therapeutic effect. Therefore, the analysis of PSA and PAP in the human serum is of great significance for the monitoring of disease status in clinical diagnosis and treatment. In this review the recent advances in the methodological study for detection of prostate cancer markers are reviewed along with the description of their structures and biological functions. The detection technologies of prostate-specific antigen and prostate acid phosphatase are emphatically introduced, which mainly contain colorimetric techniques, electrochemical methods, fluorescence methods and surface resonance plasmon techniques. On the basis of summarizing the research progress in this field in recent decades, the future development of prostate cancer marker analysis is prospected. This review is expected to provide a useful guidance for the study of prostate cancer markers.
The detection of tumor markers plays an important role in the screening, early diagnosis and treatment of high-risk cancer patients. Prostatic cancer is one of the most common malignancies of the male genitourinary system, and has an increasing trend in recent years. Its morbidity is generally influenced by region and ethnicity. The common clinical markers of prostate cancer include prostate-specific antigen (PSA), prostate-specific membrane antigen (PSMA), alpha-formyl kievase A mesozyme (AMACR, P504S), prostate-acid phosphatase (PAP), and calcium phosphatidyl binding protein 3 (ANXA3). Most of these markers are composed of proteins or enzymes, which are produced by normal or cancerous prostate cells. Of these, prostate-specific antigen (PSA) and prostate-acid phosphatase (PAP) are considered to be the most meaningful markers of the prostatic cancer. Detection of PSA is widely used in the early detection and monitoring of prostate cancer patients, while analysis of PAP is often used to detect advanced prostate cancer metastases and evaluate the therapeutic effect. Therefore, the analysis of PSA and PAP in the human serum is of great significance for the monitoring of disease status in clinical diagnosis and treatment. In this review the recent advances in the methodological study for detection of prostate cancer markers are reviewed along with the description of their structures and biological functions. The detection technologies of prostate-specific antigen and prostate acid phosphatase are emphatically introduced, which mainly contain colorimetric techniques, electrochemical methods, fluorescence methods and surface resonance plasmon techniques. On the basis of summarizing the research progress in this field in recent decades, the future development of prostate cancer marker analysis is prospected. This review is expected to provide a useful guidance for the study of prostate cancer markers.
2020, 78(11): 1223-1228
doi: 10.6023/A20080341
Abstract:
Although N-type ferrimagnets exhibit negative magnetization under positive magnetic fields, compounds that could maintain negative magnetization behavior under strong magnetic field (e.g. 1 T) are still rare. In this work, a mixed-valence metal-formate [CH3NH3]n[FeIIIFeII(HCO2)6]n (1) was constructed by the reaction of FeCl3·6H2O, formic acid and N-methyl formamide at 140 ℃ for two days. At room temperature, 1 crystallizes in the space group P31c, in which a three-dimensional anionic niccolite topological framework is constructed by FeII, FeIII ions, and anti, anti formate. The guest CH3NH3+ cations fill in the cavities of the framework as the charge balancer with the N atoms displaying threefold disorder and the atoms having a twofold disorder. The heat capacity measurement shows two different peaks, being the signatures of phase transitions. The change in heat capacity at 136 K corresponds to the phase transition triggered by the order-disorder phenomena of the CH3NH3+ cations. At low temperature phase, 1 has a symmetry of 2/m in space group C2/c, in which the threefold disorder of the N atoms of the CH3NH3+ was freezed. The order-disorder phase transition also results in dielectric relaxation in the temperature range 130~200 K at 500 Hz~1 MHz. The change of heat capacity at 40 K is associated with the ferromagnetic order of the antiferromagnetically coupled FeIII and FeII sublattices. 1 is a N-type ferrimagnet with negative magnetization below TN on cooling under the applied field, and thermo-driven magnetic poles reversal could be found in 1 with large applied field of 1 T. Furthermore, positive field regulated switchable magnetic dipoles switching of the magnetization, together with obvious huge positive exchange bias is also observed in 1. These results reveal the significant magnetic anisotropy in 1, and the guest in the framework not only can tune the structural phase transitions but also modulate the anisotropy of the host framework leading to different magnetism.
Although N-type ferrimagnets exhibit negative magnetization under positive magnetic fields, compounds that could maintain negative magnetization behavior under strong magnetic field (e.g. 1 T) are still rare. In this work, a mixed-valence metal-formate [CH3NH3]n[FeIIIFeII(HCO2)6]n (1) was constructed by the reaction of FeCl3·6H2O, formic acid and N-methyl formamide at 140 ℃ for two days. At room temperature, 1 crystallizes in the space group P31c, in which a three-dimensional anionic niccolite topological framework is constructed by FeII, FeIII ions, and anti, anti formate. The guest CH3NH3+ cations fill in the cavities of the framework as the charge balancer with the N atoms displaying threefold disorder and the atoms having a twofold disorder. The heat capacity measurement shows two different peaks, being the signatures of phase transitions. The change in heat capacity at 136 K corresponds to the phase transition triggered by the order-disorder phenomena of the CH3NH3+ cations. At low temperature phase, 1 has a symmetry of 2/m in space group C2/c, in which the threefold disorder of the N atoms of the CH3NH3+ was freezed. The order-disorder phase transition also results in dielectric relaxation in the temperature range 130~200 K at 500 Hz~1 MHz. The change of heat capacity at 40 K is associated with the ferromagnetic order of the antiferromagnetically coupled FeIII and FeII sublattices. 1 is a N-type ferrimagnet with negative magnetization below TN on cooling under the applied field, and thermo-driven magnetic poles reversal could be found in 1 with large applied field of 1 T. Furthermore, positive field regulated switchable magnetic dipoles switching of the magnetization, together with obvious huge positive exchange bias is also observed in 1. These results reveal the significant magnetic anisotropy in 1, and the guest in the framework not only can tune the structural phase transitions but also modulate the anisotropy of the host framework leading to different magnetism.
2020, 78(11): 1229-1234
doi: 10.6023/A20090424
Abstract:
Organoboron compounds are important intermediates in organic synthesis because of their high utilities for C—C and C—X bond formations. Transition metal-catalyzed borylative difunctionalization of alkenes, which can simultaneously introduce C—B, C—C or C—X bonds, could directly construct highly functionalized organoboron in one step. Among these reactions, copper catalyzed enantioselective aminoboration of styrenes is an efficient approach to generate enantioriched β-aminoboronate which is a class of useful chiral compounds. In this work, employing styrenes as substrates, 1, 2-benzisoxazole as an electrophilic primary amine source, bis(pinacolato)diboron (B2pin2) as boron source and LiOCH3 as base, an enantioselective Cu-catalyzed aminoboration of styrenes by using a chiral sulfoxide-phosphine (SOP) ligand was developed, and a board range of chiral β-aminoalkylboranes, which could be readily converted to a class of valuable β-hydroxylalkylamines, were accessed with high yields and ee values. A general procedure for this aminoboration of styrenes is described in the following: in a glove box, CuI (0.05 mmol), chiral sulfoxide phosphine ligand L1 (0.06 mmol), and 2 mL of anhydrous tetrahydrofuran were added into a flame-dried tube. The resulting mixture was stirred at room temperature for 30 min. Then bis(pinacolato)diboron (B2pin2) (0.75 mmol), LiOCH3 (1.25 mmol), styrene 1 (0.5 mmol), 1, 2-benzisoxazole (0.75 mmol) and another 2 mL of THF were added into the reaction system in sequence. The reaction tube was removed out from the glove box and stirred at 20 ℃ for 12 h. After the reaction was finished, the NMR yield was firstly determined with dimethyl terephthalate (9.7 mg, 0.05 mmol) as internal standard, then, the crude product was recovered and purified with a preparative TLC which was alkalized with triethylamine to give the desired β-aminoboronates in moderate to good yields (47%~84%) and enantioselectivities (81%~99%). To demonstrate the utility of this reaction, β-boronate primary amine could be easily obtained by removing the Schiff base group of β-aminoboronate 3 under the methanol solution of hydroxylamine hydrochloride, which could be further oxidized to give corresponding chiral β-amino alcohol in moderate yield (48%).
Organoboron compounds are important intermediates in organic synthesis because of their high utilities for C—C and C—X bond formations. Transition metal-catalyzed borylative difunctionalization of alkenes, which can simultaneously introduce C—B, C—C or C—X bonds, could directly construct highly functionalized organoboron in one step. Among these reactions, copper catalyzed enantioselective aminoboration of styrenes is an efficient approach to generate enantioriched β-aminoboronate which is a class of useful chiral compounds. In this work, employing styrenes as substrates, 1, 2-benzisoxazole as an electrophilic primary amine source, bis(pinacolato)diboron (B2pin2) as boron source and LiOCH3 as base, an enantioselective Cu-catalyzed aminoboration of styrenes by using a chiral sulfoxide-phosphine (SOP) ligand was developed, and a board range of chiral β-aminoalkylboranes, which could be readily converted to a class of valuable β-hydroxylalkylamines, were accessed with high yields and ee values. A general procedure for this aminoboration of styrenes is described in the following: in a glove box, CuI (0.05 mmol), chiral sulfoxide phosphine ligand L1 (0.06 mmol), and 2 mL of anhydrous tetrahydrofuran were added into a flame-dried tube. The resulting mixture was stirred at room temperature for 30 min. Then bis(pinacolato)diboron (B2pin2) (0.75 mmol), LiOCH3 (1.25 mmol), styrene 1 (0.5 mmol), 1, 2-benzisoxazole (0.75 mmol) and another 2 mL of THF were added into the reaction system in sequence. The reaction tube was removed out from the glove box and stirred at 20 ℃ for 12 h. After the reaction was finished, the NMR yield was firstly determined with dimethyl terephthalate (9.7 mg, 0.05 mmol) as internal standard, then, the crude product was recovered and purified with a preparative TLC which was alkalized with triethylamine to give the desired β-aminoboronates in moderate to good yields (47%~84%) and enantioselectivities (81%~99%). To demonstrate the utility of this reaction, β-boronate primary amine could be easily obtained by removing the Schiff base group of β-aminoboronate 3 under the methanol solution of hydroxylamine hydrochloride, which could be further oxidized to give corresponding chiral β-amino alcohol in moderate yield (48%).
2020, 78(11): 1235-1239
doi: 10.6023/A20080339
Abstract:
Similar to natural proteins, polypeptides can form secondary structures depending on their physical properties. Many efforts have been made towards the self-assembly of triblock copolymer containing polypeptide as an important component to construct hierarchical structures by utilizing the pH-responsive conformation transformation. In this work, a pH-responsive poly(ethylene glycol)-b-poly(L-lysine)-b-poly(styrene) (PEG-b-PLL-b-PS) triblock copolymer was prepared via a combination of controlled ring opening polymerization (ROP) and atom transfer radical polymerization (ATRP). In the triblock copolymer, PLL is water-soluble in acidic solution with random coil conformation, but becomes insoluble helix in alkaline solution. PEG has excellent water solubility that can exhibit protein-resistant property. PS serves as hydrophobic part. Self-assembly of the polymer was examined by transmission electron microscopy (TEM), atomic force microscopy (AFM) and attenuated total reflection-infrared spectrometer (ATR-IR). The triblock copolymer forms spherical micelles in 1:1 volume ratio of tetrahydrofuran-water mixed solvent, in which the hydrophobic PS segment forms a core and the two hydrophilic segments PLL and PEG serve as shell and corona, respectively. The spheres as the subunits further transform into hierarchical 1D fiber-like structure in the presence of THF after 7 d of aging, confirmed by both TEM and AFM techniques. Upon removing THF, the spherical shape was re-obtained with slightly smaller diameter, so called "frozen micelles". Further, the diameter of the spheres increases with pH increasing. A sphere-to-vesicle transition was observed at pH 13 as the secondary conformation of PLL transforms from coil to α-helix. The dialysis of these solutions can convert the vesicles back into spherical morphology with slightly smaller diameter.
Similar to natural proteins, polypeptides can form secondary structures depending on their physical properties. Many efforts have been made towards the self-assembly of triblock copolymer containing polypeptide as an important component to construct hierarchical structures by utilizing the pH-responsive conformation transformation. In this work, a pH-responsive poly(ethylene glycol)-b-poly(L-lysine)-b-poly(styrene) (PEG-b-PLL-b-PS) triblock copolymer was prepared via a combination of controlled ring opening polymerization (ROP) and atom transfer radical polymerization (ATRP). In the triblock copolymer, PLL is water-soluble in acidic solution with random coil conformation, but becomes insoluble helix in alkaline solution. PEG has excellent water solubility that can exhibit protein-resistant property. PS serves as hydrophobic part. Self-assembly of the polymer was examined by transmission electron microscopy (TEM), atomic force microscopy (AFM) and attenuated total reflection-infrared spectrometer (ATR-IR). The triblock copolymer forms spherical micelles in 1:1 volume ratio of tetrahydrofuran-water mixed solvent, in which the hydrophobic PS segment forms a core and the two hydrophilic segments PLL and PEG serve as shell and corona, respectively. The spheres as the subunits further transform into hierarchical 1D fiber-like structure in the presence of THF after 7 d of aging, confirmed by both TEM and AFM techniques. Upon removing THF, the spherical shape was re-obtained with slightly smaller diameter, so called "frozen micelles". Further, the diameter of the spheres increases with pH increasing. A sphere-to-vesicle transition was observed at pH 13 as the secondary conformation of PLL transforms from coil to α-helix. The dialysis of these solutions can convert the vesicles back into spherical morphology with slightly smaller diameter.
2020, 78(11): 1240-1245
doi: 10.6023/A20070323
Abstract:
Furin, the most characteristic member of the proprotein convertase (PCs), has important biological functions. The expression level of furin is related to many diseases, for example, the occurrence and development of cancer is closely related to the expression level of furin. Although several small-molecule fluorescent probes for furin have been developed, which were designed based on near-infrared dye or one-photon dye. These probes exhibit low Stocks' shift or shallow penetration depth, which leading to self-quenching and strong interference. Two-photon fluorescent probes, which utilize two near-infrared photons as the excitation source, can overcome these problems. Herein, a furin-activatable two-photon fluorescent probe (Nap-F) was developed firstly that allowed for detection and imaging of furin in live cells and tumor tissues. Nap-F consists of a classical two-photon fluorophore (1, 8-naphthalimide), a furin-particular polypeptide sequence RVRR and a self-eliminating linker. Nap-F is water-soluble and in a fluorescence-off state itself due to the inhibited intramolecular charge transfer (ICT). In the absence of furin, no noticeable fluorescence enhancement was detected, even over 3 days in buffer solution, indicating its good stability. Upon the conversion by furin, it displayed a dramatically fluorescence enhancement at 545 nm, and exhibits high specificity and sensitivity to furin. Nap-F was applied for visualizing the difference in the expression level of furin in various cells, demonstrating its capacity of distinguishing some cancer cells from normal cells. Furthermore, Nap-F was utilized to visualize the variation of furin expression level efficiently after immobilization of hypoxia-inducible factor-1 (HIF-1) by CoCl2, with the results indicating that there is a positive correlation between the expression level of furin and the degree of hypoxia in tumor cells. Owing to the excellent property of Nap-F, the probe was also successful utilized to imaging furin activity in tumor tissues. Thus, Nap-F is able to serve as a potential tool for better exploring the intrinsic link between hypoxic physiological environment and cellular carcinogenesis and detecting cancer in preclinical applications.
Furin, the most characteristic member of the proprotein convertase (PCs), has important biological functions. The expression level of furin is related to many diseases, for example, the occurrence and development of cancer is closely related to the expression level of furin. Although several small-molecule fluorescent probes for furin have been developed, which were designed based on near-infrared dye or one-photon dye. These probes exhibit low Stocks' shift or shallow penetration depth, which leading to self-quenching and strong interference. Two-photon fluorescent probes, which utilize two near-infrared photons as the excitation source, can overcome these problems. Herein, a furin-activatable two-photon fluorescent probe (Nap-F) was developed firstly that allowed for detection and imaging of furin in live cells and tumor tissues. Nap-F consists of a classical two-photon fluorophore (1, 8-naphthalimide), a furin-particular polypeptide sequence RVRR and a self-eliminating linker. Nap-F is water-soluble and in a fluorescence-off state itself due to the inhibited intramolecular charge transfer (ICT). In the absence of furin, no noticeable fluorescence enhancement was detected, even over 3 days in buffer solution, indicating its good stability. Upon the conversion by furin, it displayed a dramatically fluorescence enhancement at 545 nm, and exhibits high specificity and sensitivity to furin. Nap-F was applied for visualizing the difference in the expression level of furin in various cells, demonstrating its capacity of distinguishing some cancer cells from normal cells. Furthermore, Nap-F was utilized to visualize the variation of furin expression level efficiently after immobilization of hypoxia-inducible factor-1 (HIF-1) by CoCl2, with the results indicating that there is a positive correlation between the expression level of furin and the degree of hypoxia in tumor cells. Owing to the excellent property of Nap-F, the probe was also successful utilized to imaging furin activity in tumor tissues. Thus, Nap-F is able to serve as a potential tool for better exploring the intrinsic link between hypoxic physiological environment and cellular carcinogenesis and detecting cancer in preclinical applications.
2020, 78(11): 1246-1254
doi: 10.6023/A20070282
Abstract:
Polymer solar cells (PSCs) experienced a leap forward recently due to the development of non-fullerene acceptors. These novel acceptor materials possess improved photon absorption ability as well as readily tunable band structures compared to the conventional fullerenes. Perylene diimide (PDI) derivatives were among the first investigated non-fullerene acceptors for PSCs. PDI is widely adopted as building blocks for acceptor materials for its high photon absorption and electron transporting abilities, suitable and tunable energy levels, ease of synthesis and excellent photon stability. However, PDI derivatives are well known for their aggregation tendency to result in poor blend morphology, which leads to lower device efficiency than the acceptor-donor-acceptor type fused ring small molecular acceptors. To address this issue, we designed and synthesized three PDI based small molecular acceptors with a diketopyrrolopyrrole (DPP) core. The c-PDI2 and nc-PDI2 were two-PDI-armed molecules with PDI substituents attached on the carbon or nitrogen atoms of the DPP skeleton, respectively, while PDI4 was a four-PDI-armed molecule. The PDI units were predicted by molecular simulations to be positioned in altered planes forming the twisted 3D structures, which would reduce the intermolecular aggregation. Based on optical absorption, energy level, blend morphology and photovoltaic performance studies, all three molecules were found with amorphous morphology, which indicated that the aggregation tendency was efficiently suppressed. Among the three molecules, the four-armed PDI4 displayed the flatter structure with broadened electron delocalization which led to significantly increased extinction coefficient and electron transport mobility. The faster electron transport of PDI4 assured the balanced charge transport which yielded into a higher field factor (FF) over 65% in contrast to the two-armed molecules with FFs under 55% in the respective PSC devices. With additional aids from the increased photon absorption, PSCs containing PDI4 also generated substantially higher photocurrent. These improvements afforded the highest power conversion efficiency (PCE) as high as 8.45% among the three PDI derivatives, which was twice and 1.5 times of those of c-PDI2 and nc-PDI2, respectively. In comparison between the two two-armed PDI derivatives, the nitrogen-position-substituted nc-PDI2 delivered higher device performances than the carbon-position-substituted c-PDI2, also thanked to its flatter molecular arrangement and broader intra- and intermolecular electron delocalization. In our study, we successfully prevented aggregation of PDI derivatives by constructing 3D molecular structures with multiple PDI units. The numbers and substituting positions of PDIs on the DPP core were also investigated in detail, which provided valuable insights for designing of high performance PDI derivatives for PSCs.
Polymer solar cells (PSCs) experienced a leap forward recently due to the development of non-fullerene acceptors. These novel acceptor materials possess improved photon absorption ability as well as readily tunable band structures compared to the conventional fullerenes. Perylene diimide (PDI) derivatives were among the first investigated non-fullerene acceptors for PSCs. PDI is widely adopted as building blocks for acceptor materials for its high photon absorption and electron transporting abilities, suitable and tunable energy levels, ease of synthesis and excellent photon stability. However, PDI derivatives are well known for their aggregation tendency to result in poor blend morphology, which leads to lower device efficiency than the acceptor-donor-acceptor type fused ring small molecular acceptors. To address this issue, we designed and synthesized three PDI based small molecular acceptors with a diketopyrrolopyrrole (DPP) core. The c-PDI2 and nc-PDI2 were two-PDI-armed molecules with PDI substituents attached on the carbon or nitrogen atoms of the DPP skeleton, respectively, while PDI4 was a four-PDI-armed molecule. The PDI units were predicted by molecular simulations to be positioned in altered planes forming the twisted 3D structures, which would reduce the intermolecular aggregation. Based on optical absorption, energy level, blend morphology and photovoltaic performance studies, all three molecules were found with amorphous morphology, which indicated that the aggregation tendency was efficiently suppressed. Among the three molecules, the four-armed PDI4 displayed the flatter structure with broadened electron delocalization which led to significantly increased extinction coefficient and electron transport mobility. The faster electron transport of PDI4 assured the balanced charge transport which yielded into a higher field factor (FF) over 65% in contrast to the two-armed molecules with FFs under 55% in the respective PSC devices. With additional aids from the increased photon absorption, PSCs containing PDI4 also generated substantially higher photocurrent. These improvements afforded the highest power conversion efficiency (PCE) as high as 8.45% among the three PDI derivatives, which was twice and 1.5 times of those of c-PDI2 and nc-PDI2, respectively. In comparison between the two two-armed PDI derivatives, the nitrogen-position-substituted nc-PDI2 delivered higher device performances than the carbon-position-substituted c-PDI2, also thanked to its flatter molecular arrangement and broader intra- and intermolecular electron delocalization. In our study, we successfully prevented aggregation of PDI derivatives by constructing 3D molecular structures with multiple PDI units. The numbers and substituting positions of PDIs on the DPP core were also investigated in detail, which provided valuable insights for designing of high performance PDI derivatives for PSCs.
2020, 78(11): 1255-1259
doi: 10.6023/A20070317
Abstract:
The atomically precise silver(I)-thiolate clusters in nanoscale have attracted extensive attention for years due to their attractive aesthetic structures and potential applications. Herein, two novel core-shell structured silver(I)-thiolate clusters of [Ag56S12(tBuS)20(CF3CO2)12]·6CH3CN·8H2O (abbreviated as Ag56) and [Ag58S12(tBuS)20(CF3CO2)14(CH3CN)6]·6CH3CN (Ag58) are prepared by employing the self-assembly method in solution. Especially, with the introduction of dimethylformamide (DMF) and bis(diphenylphosphino)methane (DPPM), the tBuSAg precursor reacted with CF3CO2Ag to produce a novel cluster Ag58 instead of Ag56 that has a similar structure with previous reports. X-ray structural analysis indicates that both clusters have Ag14 core units. But different from the common dodecahedron structure in Ag56, the spindle-shaped Ag14 structure in Ag58 is discovered for the first time and then induces the shell structure of Ag58 to form a rare spindle shape, in which silver atoms are layered in a form of "Ag4-Ag8-Ag10-Ag10-Ag8-Ag4". Notably, the spindle-shaped Ag14 is formed by rhombic dodecahedron being symmetrically pulled outward. Thus, there are obvious similarities and differences between the two Ag14 core structures. Compared with the previously reported the face-centered cubic Ag14 prepared by solvothermal methods, the rhombic dodecahedron and the rhombic dodecahedron-like (spindle) Ag14 were obtained at room temperature, which indicates that the formation of the clusters is a thermodynamic control. However, the change of solvent and auxiliary ligands also caused the Ag14 rhombohedral dodecahedron to deform and transform into a spindle-shaped structure, proving that the formation of the clusters is also a process controlled by kinetics. These prove that the synthesis of clusters is a process dominated by both of kinetics and thermodynamics. The UV-Vis absorption and fluorescence spectra show that the structure discrepancies of the two clusters deriving from the isomerization of Ag14 units significantly affect the energy levels and fluorescence properties of the clusters. This study enriches the thiolate-silver cluster family and provides new samples and insights for understanding the formation mechanism and properties of such core-shell architectures.
The atomically precise silver(I)-thiolate clusters in nanoscale have attracted extensive attention for years due to their attractive aesthetic structures and potential applications. Herein, two novel core-shell structured silver(I)-thiolate clusters of [Ag56S12(tBuS)20(CF3CO2)12]·6CH3CN·8H2O (abbreviated as Ag56) and [Ag58S12(tBuS)20(CF3CO2)14(CH3CN)6]·6CH3CN (Ag58) are prepared by employing the self-assembly method in solution. Especially, with the introduction of dimethylformamide (DMF) and bis(diphenylphosphino)methane (DPPM), the tBuSAg precursor reacted with CF3CO2Ag to produce a novel cluster Ag58 instead of Ag56 that has a similar structure with previous reports. X-ray structural analysis indicates that both clusters have Ag14 core units. But different from the common dodecahedron structure in Ag56, the spindle-shaped Ag14 structure in Ag58 is discovered for the first time and then induces the shell structure of Ag58 to form a rare spindle shape, in which silver atoms are layered in a form of "Ag4-Ag8-Ag10-Ag10-Ag8-Ag4". Notably, the spindle-shaped Ag14 is formed by rhombic dodecahedron being symmetrically pulled outward. Thus, there are obvious similarities and differences between the two Ag14 core structures. Compared with the previously reported the face-centered cubic Ag14 prepared by solvothermal methods, the rhombic dodecahedron and the rhombic dodecahedron-like (spindle) Ag14 were obtained at room temperature, which indicates that the formation of the clusters is a thermodynamic control. However, the change of solvent and auxiliary ligands also caused the Ag14 rhombohedral dodecahedron to deform and transform into a spindle-shaped structure, proving that the formation of the clusters is also a process controlled by kinetics. These prove that the synthesis of clusters is a process dominated by both of kinetics and thermodynamics. The UV-Vis absorption and fluorescence spectra show that the structure discrepancies of the two clusters deriving from the isomerization of Ag14 units significantly affect the energy levels and fluorescence properties of the clusters. This study enriches the thiolate-silver cluster family and provides new samples and insights for understanding the formation mechanism and properties of such core-shell architectures.
2020, 78(11): 1260-1267
doi: 10.6023/A20070285
Abstract:
In order to search for novel anti-diabetes molecules, phenformin (Phf) was used as precursors to prepare chromium(Ⅲ) complex [Cr(Phf)3]Cl3 at room temperature. The complex was characterized by elemental analysis (EA), molar conductivity (MC), electrospray ionization mass spectrometry (ESI-MS), infrared (IR), UV-vis and NMR spectroscopy, respectively. In this work, the stability of complex solutions at different temperatures and pH values, reactivity with H2O2 were discussed in detail. The morphology and thermal studies of the complex were also investigated. Meanwhile, C57 diabetic mouse model induced by diet combined with streptozocin (STZ) was established to explore its biological activity from the aspects of fasting blood glucose (FBG), fasting serum insulin (FINS), total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-c), low density lipoprotein cholesterol (LDL-c) levels, and oral toxicity. Afterwards, in order to explore the biological hypoglycemic mechanism of the complex, the interaction between the complex and glucagon was studied at (37±0.5) ℃ in Phosphate Buffer Saline (PBS) buffer at pH 7.4 by fluorescence spectra, which the conditional binding constant K is 1.29×105 L·mol-1, and the number of binding sites n is about 1. As a result, the interaction between the complex and glucagon was static quenching. The complex which retained the glucose-lowering properties of Phf exhibited good physical and chemical properties, beneficial function on blood glucose and lipid metabolism for Type Ⅱ Diabetes mellitus (T2DM). The glucose-lowering mechanism of the complex was proposed, and the multi-functional application of metal complex in glucose-lowering and lipid-controlling was also achieved. Furthermore, oral toxicity results showed that the complex had no toxicity on all organs of mice. Methyl Thiazolyl Tetrazolium (MTT) assays also showed that the complex exhibited lower cytotoxicity than the positive control CrCl3 and Phf. Taken together, these results demonstrated that the non-toxic [Cr(Phf)3]Cl3 complex might be a potential candidate for novel anti–diabetic drug development. It may also provide a new idea for the prevention and treatment of type 2 diabetes.
In order to search for novel anti-diabetes molecules, phenformin (Phf) was used as precursors to prepare chromium(Ⅲ) complex [Cr(Phf)3]Cl3 at room temperature. The complex was characterized by elemental analysis (EA), molar conductivity (MC), electrospray ionization mass spectrometry (ESI-MS), infrared (IR), UV-vis and NMR spectroscopy, respectively. In this work, the stability of complex solutions at different temperatures and pH values, reactivity with H2O2 were discussed in detail. The morphology and thermal studies of the complex were also investigated. Meanwhile, C57 diabetic mouse model induced by diet combined with streptozocin (STZ) was established to explore its biological activity from the aspects of fasting blood glucose (FBG), fasting serum insulin (FINS), total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-c), low density lipoprotein cholesterol (LDL-c) levels, and oral toxicity. Afterwards, in order to explore the biological hypoglycemic mechanism of the complex, the interaction between the complex and glucagon was studied at (37±0.5) ℃ in Phosphate Buffer Saline (PBS) buffer at pH 7.4 by fluorescence spectra, which the conditional binding constant K is 1.29×105 L·mol-1, and the number of binding sites n is about 1. As a result, the interaction between the complex and glucagon was static quenching. The complex which retained the glucose-lowering properties of Phf exhibited good physical and chemical properties, beneficial function on blood glucose and lipid metabolism for Type Ⅱ Diabetes mellitus (T2DM). The glucose-lowering mechanism of the complex was proposed, and the multi-functional application of metal complex in glucose-lowering and lipid-controlling was also achieved. Furthermore, oral toxicity results showed that the complex had no toxicity on all organs of mice. Methyl Thiazolyl Tetrazolium (MTT) assays also showed that the complex exhibited lower cytotoxicity than the positive control CrCl3 and Phf. Taken together, these results demonstrated that the non-toxic [Cr(Phf)3]Cl3 complex might be a potential candidate for novel anti–diabetic drug development. It may also provide a new idea for the prevention and treatment of type 2 diabetes.
2020, 78(11): 1268-1274
doi: 10.6023/A20070319
Abstract:
The layered lithium-rich manganese-based cathode material has been widely concerned because of it's advantages such as a specific discharge capacity greater than 250 mAh·g-1 and a high discharge platform, and is expected to become the next-generation lithium ion battery cathode material. However, lithium-rich manganese-based cathode materials have poor cycle stability, low coulombic efficiency for the first charge and discharge, and low rate performance. The most important thing is that the problem of faster voltage decays on the discharge platform has not been effectively solved, The current it is mainly to improve the performance by element doping modification and surface coating, so it is very important to find suitable doping elements and coating materials. The common coating material is mainly to prevent direct contact between the electrolyte and the positive electrode material to improve the cycle stability, and it is difficult to slow down the attenuation of the discharge voltage platform. Al-doping lithium-rich manganese-based Li1.2Mn0.54-xAlxNi0.13Co0.13O2 (x=0, 0.03) cathode material was prepared by sol-gel method and Li2WO4 surface coating by one-step liquid phase method. The required materials were confirmed by X-ray diffractometer (XRD), energy disperse spectroscopy (EDS) and scanning electron microscope (SEM) tests, and then the effects of Al-doping and Li2WO4 coated double-effect modification on the electrochemical performance of lithium-rich manganese-based cathode materials were studied by electrochemical test system. The results show that Al doping significantly improves the cycling stability of lithium-rich manganese-based cathode materials, and the coating Li2WO4 significantly improves its rate performance and discharge platform voltage attenuation. In 5% Li2WO4 coated Li1.2Mn0.51Al0.03Ni0.13Co0.13O2 cathode material in charge and discharge voltage 2.0~4.8 V, and under the current density 1000 mA·g-1, the specific capacity is still as high as about 110 mAh·g-1. At the same time, the specific capacity retention rate was 78% after 300 cycles at the current density of 100 mA·g-1, and the voltage decay of the discharge platform significantly slowed down during the cycle.
The layered lithium-rich manganese-based cathode material has been widely concerned because of it's advantages such as a specific discharge capacity greater than 250 mAh·g-1 and a high discharge platform, and is expected to become the next-generation lithium ion battery cathode material. However, lithium-rich manganese-based cathode materials have poor cycle stability, low coulombic efficiency for the first charge and discharge, and low rate performance. The most important thing is that the problem of faster voltage decays on the discharge platform has not been effectively solved, The current it is mainly to improve the performance by element doping modification and surface coating, so it is very important to find suitable doping elements and coating materials. The common coating material is mainly to prevent direct contact between the electrolyte and the positive electrode material to improve the cycle stability, and it is difficult to slow down the attenuation of the discharge voltage platform. Al-doping lithium-rich manganese-based Li1.2Mn0.54-xAlxNi0.13Co0.13O2 (x=0, 0.03) cathode material was prepared by sol-gel method and Li2WO4 surface coating by one-step liquid phase method. The required materials were confirmed by X-ray diffractometer (XRD), energy disperse spectroscopy (EDS) and scanning electron microscope (SEM) tests, and then the effects of Al-doping and Li2WO4 coated double-effect modification on the electrochemical performance of lithium-rich manganese-based cathode materials were studied by electrochemical test system. The results show that Al doping significantly improves the cycling stability of lithium-rich manganese-based cathode materials, and the coating Li2WO4 significantly improves its rate performance and discharge platform voltage attenuation. In 5% Li2WO4 coated Li1.2Mn0.51Al0.03Ni0.13Co0.13O2 cathode material in charge and discharge voltage 2.0~4.8 V, and under the current density 1000 mA·g-1, the specific capacity is still as high as about 110 mAh·g-1. At the same time, the specific capacity retention rate was 78% after 300 cycles at the current density of 100 mA·g-1, and the voltage decay of the discharge platform significantly slowed down during the cycle.
