MICROCHIMICA ACTA
·
2020
·Vol. 187
·期 4
·1-9
·
IF 6.232
Huang Xuemin,Zhao Huanan,Qiu Wen,Wang Jian,Guo Longhua,Lin Zhenyu,Pan Wei,Wu Yong,Qiu Bin
A fluorescence resonance energy transfer (FRET)-based in situ fluorescence signal amplification strategy is described for the determination of tyrosinase (TYR). In this assay, a dual-templated copper nanocluster (CuNCs) stabilized by bovine serum albumin (BSA) and glycylglycine (Gly-Gly) was used as an energy donor. Metyrosine was employed as a TYR substrate because its enzyme catalytic product (methyldopa) was able to function as a monomer molecule to form fluorescent polymethyldopa (PMeDP) with the assistance of BSA/Gly-Gly CuNCs. In this process, PMeDP can combine with BSA/Gly-Gly CuNCs without extra modification and then acts as an energy receptor, which leads to a remarkable FRET from BSA/Gly-Gly CuNCs to PMeDP. Interestingly, the fluorescence intensity of PMeDP was strengthened greatly in the FRET-based sensor compared to the separate excitation, which provided good sensitivity for TYR sensing. Illuminated under a UV light source, the fluorescence signal change is observed from dark violet to bright green. Therefore, the present sensing system affords a reliable ratiometric assay for TYR determination. Also, the ratio of fluorescence intensity between PMeDP ( λ em at 505 nm, F505) and BSA/Gly-Gly CuNCs ( λ em at 415 nm, F415) was used for quantitative determination of TYR. The sensing system was easily operated in aqueous media with an exciting detection limit of 44.0 U L −1 . This sensing strategy has been applied to the screening of inhibitors.
Schematic representation of the strategy for the determination of tyrosinase.
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BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY
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2020
·Vol. 104
·期 4
·477-483
·
IF 1.657
Liu Yaxin,Xu Kun,Cheng Jiemin
The application of nano-level passivating agents in the remediation of soil heavy metal pollution has received widespread attention, but its harm to soil animals should also be addressed. This study explored the effect of three nanomaterials—nanohydroxyapatite apatite (n-HAP), nano zeolite (n-zeolite), and nanometer iron oxide (n-Fe 3 O 4 ), on catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) activity and malondialdehyde (MDA) content through filter paper contact test. The effects of nanomaterials spiked at 1.5%wt of soils on earthworm avoidance behavior were also be studied, and the crystallinity and surface charge of three nanomaterials were characterized. The results showed that the activities of CAT, SOD and POD and the content of MDA have been changed at different level. And earthworms have obvious avoidance behavior to the three kinds of nanomaterials. Therefore, nanomaterials do have adverse effects on earthworms, and their biological toxicity should be considered when selecting passivating agents for soil heavy metal pollution remediation.
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NPG Asia Materials
·
2020
·Vol. 12
·期 1
·1-11
·
IF 8.131
Sun Ao,He Xinye,Li Lang,Li Tao,Liu Qinya,Zhou Xinli,Ji Xiao,Li Wei,Qian Zhiyong
Abstract Currently, wound infection is an important health problem for the public. Wound infection can not only hinder healing but it can also lead to serious complications. Injectable wound dressings with biocompatible and antibacterial properties can promote wound healing during skin infections and reduce antibiotic use. Here, we used glycidyl methacrylate (GMA) to modify ε-polylysine (ε-PL) and γ-poly(glutamic acid) (γ-PGA) to produce ε-polylysine-glycidyl methacrylate (ε-PL-GMA) and γ-poly(glutamic acid)-glycidyl methacrylate (γ-PGA-GMA). Subsequently, ε-PL-GMA- and γ-PGA-GMA-based hydrogels were developed through photopolymerization using visible light. The hydrogels were injectable, could rapidly gelatinize, were biocompatible, and showed a wide spectrum of antibacterial activity. The hydrogels also promoted wound healing. The results show that these hydrogels inhibit bacterial infection and shorten the wound healing time of skin defects in Staphylococcus aureus models. This demonstrates that the hydrogels hold potential for clinical antimicrobial and wound healing therapy.
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JOURNAL OF SOLID STATE ELECTROCHEMISTRY
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2020
·Vol. 24
·期 4
·941-950
·
IF 2.646
Yang Pan,Li Wenjuan,Lian Yijun,Yu Feng,Dai Bin,Guo Xuhong,Liu Zhiyong,Peng Banghua
Photoelectrocatalytic (PEC) water splitting technology is used to convert solar energy into hydrogen energy, and has the potential to alleviate energy crisis problem. TiO 2 nanowire arrays (NAs), as a promising PEC photoanode, have the advantages of low cost and stable mechanical properties. However, due to its wide energy band, poor conductivity, and slow carrier transfer kinetics, modifying TiO 2 NAs with metal is a feasible way to achieve high PEC performance, especially cobalt-based compounds. Different from the fussy and polluted synthesizing methods, here, we use a facile method to successfully load Co 3 O 4 and CoO mixtures on TiO 2 NAs. A series of characterization methods are conducted to study the morphology, structure, and PEC water oxidation performance. It is found that the photocurrent density of the obtained CoO-Co 3 O 4 /TiO 2 photoelectrode is enhanced and good stability can be kept up for 13 h or more. The prominent reason for enhanced PEC performance of CoO-Co 3 O 4 /TiO 2 NAs is that loading CoO and Co 3 O 4 can increase the light absorption, reduce the charge transfer resistance, and improve the charge separation efficiency of TiO 2 NAs. Our work introduces an alternative designing way to load both of CoO and Co 3 O 4 on photoelectrode in a particularly eco-benign way, which provides efficient and stable cobalt-based TiO 2 photoanodes, and it can be applied to wider research fields, such as solar cells and photo-responsive devices.
CoO x /TiO 2 NAs were synthesized via a facile approach. Because of accelerated charge transfer kinetics and enlarged light absorption capability, it exhibits superior PEC water oxidation and higher stability performance.
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CHEMICAL PAPERS
·
2020
·Vol. 74
·期 11
·4125-4133
·
IF 1.68
Wang Faqiang,Chen Lei,Xu Dong,Li Zhanxiong
Tetrafluoro-λ 6 -sulfanyl (–SF 4 –) was synthesized via oxidative fluorination and used as a bridging group to bond perfluoroalkyl to phenylene. As a result, perfluoroalkylphenyltrichlorosilane was prepared by hydrosilylation using perfluoroalkylstyrene as a raw material under platinum catalytic conditions. And the corresponding monolayers produced a coating on silicon surfaces by spontaneous self-assembly from solution. Due to the introduction of –SF 4 –, it can increase the shielding effect of the fluoroalkyl group and reduce the surface energy of the material on the basis of extending the length of the perfluoroalkyl chain. At the same time, the sulfur–carbon bond formed by the bridge group is more likely to decrease under ultraviolet light. Once the bridge bond is broken, the perfluoroalkyl-terminated carbon chain perfluoroalkyl group is decomposed and detached. Therefore, the fluorine-containing material has good ultraviolet light degradation property, and the obtained fluorine-containing material is environmentally friendly. The self-assembled film containing a perfluoroalkylsilane can effectively reduce the friction properties and adhesion of the substrate, and the substrate modified with the self-assembled film containing a perfluoroalkylsilane has good stability.
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RARE METALS
·
2020
·Vol. 40
·期 2
·374-382
·
IF 2.161
He Si-Ru,Zou Jian-Peng,Chen Li-Bao,Chen Yue-Jiao
Abstract In this work, nickel/T-Nb 2 O 5 nanoparticles encapsulated in mesoporous carbon nanofibers (denoted as Ni/T-Nb 2 O 5 @CNFs) are successfully prepared through a simple electrospinning route and succedent heating treatment. The presence of Ni in carbon nanofibers is beneficial for enhancing the electronic conductivity and the initial Coulombic efficiency. Ni/T-Nb 2 O 5 nanoparticles are homogeneously incorporated in carbon nanofibers to form a nanocomposite system, which provides effective buffering during the lithiation/delithiation process for cycling stability. The Ni/T-Nb 2 O 5 @CNFs show high surface area (26.321 m 2 ·g −1 ) and mesoporous microstructure, resulting in higher capacity and excellent rate performance. The Ni/T-Nb 2 O 5 @CNFs exhibit a remarkable capacity of 437 mAh·g −1 at a current density of 0.5 A·g −1 after 230 cycles and a capacity of 173 mAh·g −1 at a current density up to 10.0 A·g −1 after 1400 cycles. This work indicates that nickel/T-Nb 2 O 5 nanoparticles encapsulated in carbon nanofibers can be a promising candidate for anode material in high-power LIBs. Graphic abstract
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POLYMER BULLETIN
·
2020
·Vol. 78
·期 5
·2483-2503
·
IF 2.014
Mao Hui,Wang Weiji,Ma Yongle,Huang Yan
An anionic polymer P (ANAN) of acrylamide, N -vinyl-2-pyrrolidone and 2-acrylamide-2-methylpropanesulfonic acid was synthesized through free radical polymerization and initiated by 2,2′-Azobis (2-methylpropionamide) dihydrochloride as an anti-high temperature and anti-calcium and magnesium contamination fluid loss control additive for water-based drilling fluid. The P (ANAN) was characterized by 13 C-NMR and 1 H-NMR, FTIR, elemental analysis and GPC analysis. The fluid loss tests were carried on different WBDFs. The results showed that this polymer can resist 4.5 × 10 5 ppm of Cl −1 , 4 × 10 5 ppm of Ca 2+ contamination at low pH environment caused by acid gas invasion in drilling fluid at 180 °C. The fluid loss control mechanisms of P (ANAN) were investigated by Zeta potential analysis, particle size distribution analysis and mud cake quality analysis. The thermal stability was investigated by TGA analysis. The results illustrate that the P (ANAN) exhibits a stronger interaction with clays and higher-temperature resistance, and it can improve the colloidal dispersion property obviously for drilling fluid under salts, calcium and magnesium contamination and even under circumstances of acid gas invasion conditions. Due to its superior fluid loss control properties, the P (ANAN) can be a promising polymer for water-based drilling fluid in deep and ultra-deep well drilling applications.
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CELLULOSE
·
2020
·Vol. 27
·期 10
·5955-5970
·
IF 4.21
Sun Lijian,Yang Shuaishuai,Qian Xueren,An Xianhui
Abstract In the current study, we introduce “click chemistry” as a powerful tool to tailor cyclodextrin–cellulose combination product followed by the inclusion of ciprofloxacin hydrochloride (CipHCl) as antibacterial agent. Initially, beta-cyclodextrin (β-CD) and cellulose fibers (CFs) were modified so as to be mono-6-propargylamino-6-deoxy-β-CD (Pro-β-CD) and azidated cellulose fibers (CFs-N 3 ), respectively. Afterward, the “click reaction” was carried out between Pro-β-CD and CFs-N 3 to fabricate a covalent grafting of β-CD onto CFs resulting in click product (CFs-N 3 @Pro-β-CD). The drug-delivery kinetics of the loaded CipHCl was performed by immersing samples into an aqueous solution, and the amount of adsorbed and released CipHCl was measured, as a function of time, by UV spectroscopy. Compared to original CFs, the load quantity of CipHCl into the click product was greatly increased, the release time of CipHCl from CFs-N 3 @Pro-β-CD was prolonged, and considerably higher antibacterial activity against E. coli and S. aureus was observed. The click product exhibited excellent antibacterial activity and sustained antibacterial efficacy up to 12 and 10 days against S. aureus and E. coli . The results showed that β-CD has been successfully grafted onto CFs via covalent bonds, while maintaining the intrinsic properties and the integrity of the fibers. Compared with the control paper sheet, the mechanical properties of the paper are well preserved. Graphic abstract
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JOURNAL OF POLYMER RESEARCH
·
2020
·Vol. 27
·期 6
·1-9
·
IF 2.426
Zhao Xuanchen,Bi Yuanjing,Song Shixin,Liu Chuang,Lv Xue,Sun Shulin
The researches on how to prepare the polymer composites with high dielectric constant (high-k) and low dielectric loss were important for the rapid development of electronic industry. In this paper, by using silane coupling agent, the multi-wall carbon nanotubes (MWCNTs) could graft the thiol groups with high chain transfer constant on the surface, which made the polystyrene (PS) chain coat more efficiently on the surface of MWCNTs to form the core-shell structure. 1 H NMR, TGA and TEM results, showed polystyrene were grafted on the surface of MWCNTs. The grafted PS could reduce the dielectric loss of composite materials and promote the dispersion of the coating MWCNTs in the matrix. In addition, the insulating layer effectively improved the interaction between the MWCNTs and PS matrix, which strengthened the binding force between the filler and matrix, resulting in the increase of the thermal stability of the PS composites. In terms of AC conductivity, the insulating layer could effectively prevent the contact between adjacent MWCNTs from forming a complete conducting network, which inhibited the generation of leakage current. Therefore, compared with untreated multi-wall carbon nanotubes/polystyrene composites, the above composites had excellent dielectric properties with high dielectric constant (214) and low dielectric loss (2.23) at low CNTs mass fraction (4 wt%).
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Nature Communications
·
2020
·Vol. 11
·期 1
·1-11
·
IF 12.121
Zhang Qizhan,Zhou Minghua,Ren Gengbo,Li Yawei,Li Yanchun,Du Xuedong
Hydrogen peroxide (H 2 O 2 ) synthesis by electrochemical oxygen reduction reaction has attracted great attention as a green substitute for anthraquinone process. However, low oxygen utilization efficiency (<1%) and high energy consumption remain obstacles. Herein we propose a superhydrophobic natural air diffusion electrode (NADE) to greatly improve the oxygen diffusion coefficient at the cathode about 5.7 times as compared to the normal gas diffusion electrode (GDE) system. NADE allows the oxygen to be naturally diffused to the reaction interface, eliminating the need to pump oxygen/air to overcome the resistance of the gas diffusion layer, resulting in fast H 2 O 2 production (101.67 mg h -1 cm -2 ) with a high oxygen utilization efficiency (44.5%–64.9%). Long-term operation stability of NADE and its high current efficiency under high current density indicate great potential to replace normal GDE for H 2 O 2 electrosynthesis and environmental remediation on an industrial scale.
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Science China-Chemistry
·
2020
·Vol. 63
·期 5
·731-740
·
IF 6.356
Wang Yingfei,Li Yuyi,Zhang Yue,Ren Kewei,Ju Huangxian,Liu Ying
Array based detection techniques with fluorescence signal reading is a powerful tool for multiple targets analysis. However, when applied fluorescence array for microRNA detection, time-consuming multi-steps surface signal amplification is usually required due to the low abundance of microRNA in total RNA expressions, which impairs detection efficiency and limits its application in point of care test (POCT) manner. Herein, DNA cascade reactors (DCRs) functionalized photonic crystal (PC) array was fabricated for express and sensitive detections of miRNA-21 and miRNA-155. DCRs were assembled by interval conjugation of self-quenched hairpin DNA probes to single strand DNA nanowire synthesized by rolling circle amplification, which generated cascade DNA hybridization reactions in response to target miRNA with instant fluorescence recovery signal. PC array patterns with multi-structure colors further amplified fluorescence with their respective photonic bandgaps (PBGs) matching with the emission peaks of fluorescence molecules labelled on DCRs. The as-prepared DCRs functionalized PC array demonstrated express and sensitive simultaneous detections of miRNA-21 and miRNA-155 with hundreds fM detection limits only in 15 min, and was successfully applied in fast quantifications of low abundance miRNAs from cell lysates and spiked miRNAs from human serum, which would hold great potential for disease diagnosis and therapeutic effect monitoring with a POCT manner.
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MICROCHIMICA ACTA
·
2020
·Vol. 187
·期 3
·1-10
·
IF 6.232
Huang Bo,Liu Xing-Pei,Chen Jing-Shuai,Mao Chang-jie,Niu He-Lin,Jin Bao-Kang
An electrochemiluminescence (ECL) biosensor was fabricated for the evaluation of prostate specific antigen (PSA). The sensor was developed by successively modifying glassy carbon electrode (GCE) electrodes with CdS/Chito/g-C 3 N 4 nanocomposites and DNA1 was labeled at the 5′ end with thiol. The aptamer DNA was labeled at the 3′ end with a quencher ferrocene (Fc) was ligated to DNA1 by the principle of complementary base pairing. In the absence of PSA, the ECL intensity signal is effectively quenches through the energy transfer and photoexcitation electron transfer between CdS/Chito/g-C 3 N 4 emitter and quencher Fc. After incubation with target PSA, the aptamer DNA interacts with PSA and then moved away from the electrode surface together, which will recover the ECL intensity. Under the optimal conditions, the ECL intensity increases linearly with the logarithm of PSA concentration in the range of 1 pg·mL −1 to 100 ng·mL −1 , and the detection limit is 0.14 pg·mL −1 (S/ N = 3). The biosensor has been successfully applied to the determination of PSA in serum sample.
Schematic representation of the electrochemiluminescence sensor based on a CdS/chitosan/g-C 3 N 4 nanocomposite, which can be applied to the determination of prostate specific antigen in serum.
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