ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Jiajun Wang,Shyam Kattel,Zongyuan Wang,Jingguang G. Chen,Chang-Jun Liu
Pt-based materials are the most efficient catalysts for the oxygen reduction reaction (ORR) in proton-exchange membrane fuel cells. However, fabrication of active and stable Pt catalysts still remains challenging. In this work, Pt-l-phenylalanine (Pt-LPHE) films, with highly dispersed Pt nanoparticles (NPs) featuring predominately (111) facets, have been prepared via a room-temperature electron reduction method. Loading Pt-LPHE onto carbon support produces a novel nanomaterial (Pt-AL/C), resulting in a simultaneous loading of highly dispersed Pt NPs and N doping. Density functional theory calculations demonstrate that the N dopants stabilize the Pt NPs and reduce the *O/*OH binding energies on the Pt NPs. As a result, the Pt-AL/C nanomaterial shows significantly enhanced ORR activity and stability over commercial Pt/C after 10 000 cycle stability tests. This work provides a novel eco-friendly and energy-neutral approach for preparing metal NPs with controllable structures and sizes.
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
·
2018
·
IF 2.891
Zhangbao Chen,Shanshan Wang,Xiaoming Yang
Herein, one type of carbon dots (CDs) directed by l -threonine has been innovatively synthesized on the basis of a facile approach. Meanwhile, the CDs mainly consisted of C, O, N, and P according to the detailed characterizations. Importantly, the CDs obtained here not only exhibited the bright-blue fluorescence and generally acceptable stability, but also showed the promising for detecting Au 3+ and l -methionine. To be specific, the off-process by an obvious fluorescence quenching of the CDs achieved assaying Au 3+ , and Au 3+ could be removed by the introduction of l -methionine through the stronger interaction between Au 3+ and l -methionine, and thus leading to the fluorescence of CDs recovered. Consequently, the quantitative analyses of Au 3+ concentration in a linear range of 6 μM–1 mM was obtained along with the range from 80 μM to 1 mM for l -methionine. In addition, the practicability of this proposed method was validated by the detections of the lake samples, suggesting that it could broaden the sensing strategies for assaying both Au 3+ and l -methionine.
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2018
·
IF 3.909
Linlin Li,Hualin Wang,Chongyang Jin,Minmin Chen,Suwei Jiang,Junfeng Cheng,Shaotong Jiang
Zn (II) coordination compounds have aroused growing attentions as antibacterial entities. In the present work, we fabricated a new antibacterial complex of l ‑phenylalanine‑oxidized starch-coordinated zinc (II) ( l ‑Phe-OSt → Zn (II)) by successive reactions of oxidization, Maillard and coordination. Maillard reaction occurred between l ‑Phe and OSt to form l ‑Phe-OSt, which was then coordinated with Zn (II) by carboxyl groups for l ‑Phe-OSt → Zn (II). The complex showed good antibacterial activity and the antibacterial activity against E. coli was slightly poorer than B. subtilis . The presence of complex favored the generation of reactive oxygen species (ROS) in bacteria and the ROS level in B. subtilis was higher than that in E. coli . Furthermore, the toxicity of l ‑Phe-OSt → Zn (II) towards HT-29 cells was very low. The characteristics of better antibacterial activity and less cytotoxicity endow l ‑Phe-OSt → Zn (II) a great potential of application as a food additive.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
EUROPEAN POLYMER JOURNAL
·
2019
·
IF 3.621
Yajun Ren,Xinxiang Cui,Lei Wang,Yanhe Wang,Libin Han,Qifeng Zhou,Xiaofeng Song
Thermo-responsive shape memory polymers which are a class of important smart materials can recover permanent shape from temporary shape by simple thermal stimulus, but most of the polymers lack of biodegradability and biocompatibility. Poly(L-lactide) (PLLA) is a green degradable thermoplastic, however, only limited studies involve controlling its shape change. In the work, a new x -shaped copolymer with defined architecture has been devised by using tetramethyltetravinylcyclotetrasiloxane (D 4 vi ) as centronucleus and polytetrahydrofuran- co -poly( ε -caprolactone) (PTMG- co -PCL) as branch to achieve PLLA shape memory. When the weight ratio of DAPP and PLLA is 50/50, the composite exhibits good thermo-responsive shape memory capacity because a balance between T m of the x -shaped polymer rand T g of PLLA is kept. The shape fixation ratio is 84% at 15 °C, and the recovery ratio 94% at 55 °C. And the shape memory capability does not change evidently after the reversible spiral transition is repeated for 30 times. At the same time, the composite shows great flexibility. So the obtained composite is promising for medical and bionic devices, self-healing systems, self-assembly structures.
✓ 已验证
产品关联
DOI
高影响因子
Polymer Chemistry
·
2014
·Vol. 6
·期 10
·1758-1767
·
IF 5.368
Qinghua Xu,Chaoliang He,Chunsheng Xiao,Shuangjiang Yu,Xuesi Chen
Facile synthesis of biopolymers that facilitate versatile post-polymerization modification is of great interest for biotechnological and biomedical applications. In this study, a methacryloyl-substituted L-lysine N-carboxyanhydride (LysMA-NCA) monomer was designed and synthesized, and methacryloyl-functionalized polypeptides were prepared through the ring opening polymerization (ROP) of the L-lysine-based monomer. The post-polymerization functionalization of the methacryloyl-containing polypeptides with various thiol-containing molecules was achieved with high efficiency through facile radical-mediated thiol–ene chemistry. Moreover, a block copolypeptide bearing both methacryloyl and alkynyl pendants was developed through successive ROP of LysMA-NCA and γ-propargyl-L-glutamate (PPLG-NCA). The sequential modification of the block copolypeptide with hydrophilic and hydrophobic molecules, respectively, was achieved by the successive alkyne–azido and thiol–ene “click” reactions. Overall, the facile synthesis of polypeptides bearing functional substituents and their versatile post-polymerization modification may serve as a useful platform for the development of various functional polymers.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2013
·Vol. 129
·期 6
·3459-3465
·
IF 1.395
Shen Liu,Shenghe Liu,Xudong Liu,Jingwen Zhao,Wenguo Cui,Cunyi Fan
Electrospun fibrous membranes have been used frequently in biomedical applications, but their simultaneous use as antibacterial agents and in the prevention of cell adhesion on repaired tendons after injury has not been investigated. In this study, silver-nanoparticle (SN)-loaded poly( L -lactide) (PLLA) fibrous membranes were prepared by the electrospinning of SNs into PLLA fibers. Micrograph results showed that these membranes were composed of electrospun fibers and that the fibers were incorporated with SNs. From the results of X-ray diffraction and thermogravimetry, we concluded that the SNs were physically mixed into the fibers at the desired content. The mechanical properties were not significantly changed. The preliminary antibacterial effects on Staphylococcus epidermidis and Staphylococcus aureus and the synergistic antiproliferative effects of the SN-loaded PLLA fibrous membranes were observed. Taken together, these results demonstrate that SNs can be directly loaded onto a biodegradable PLLA fibrous membrane via electrospinning to achieve proper material properties with preliminary potential as antibacterial antiadhesion barriers for tendon injury. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
✓ 已验证
产品关联
DOI
高影响因子
EUROPEAN FOOD RESEARCH AND TECHNOLOGY
·
2014
·Vol. 240
·期 4
·743-751
·
IF 1.387
Zhou Cunliu,Ye Huiqiong,Wang Hui,Qin Hao,Li Junhong
This work evaluated the effects of l -arginine on the stability of porcine hemoglobin concentrates during storage. The addition of l -arginine increased both the oxyhemoglobin content and a* values but decreased both the methemoglobin content and free iron content ( p < 0.05) during storage. The addition of iron cation decreased both the oxyhemoglobin content and a* values but increased both the methemoglobin content and free iron content ( p < 0.05). CD spectra disclosed that the free iron induced the transformation of the hemoglobin secondary structure from an α-helix to a β-pleated, β-turn, and random-coil arrangement, while l -arginine hindered the behavior of the free iron. Infrared spectra revealed that the l -arginine coordinated with the free Fe 2+ or Fe 3+ to form the corresponding complex at 25 °C and pH 7.3. These results showed that l -arginine enhanced the stability of hemoglobin concentrates by coordinating with free iron.
✓ 已验证
产品关联
DOI
高影响因子
ANALYST
·
2014
·Vol. 140
·期 3
·797-802
·
IF 3.906
Chong Sun,Daoying Wang,Muhan Zhang,Yanxiu Ni,Xiaohui Shen,Youchao Song,Zhiming Geng,Weimin Xu,Fang Liu,Chun Mao
The development of advanced nanomaterials for the highly efficient electrical detection of biological species has attracted great attention. Here, novel polypyrrole-Pluronic F127 nanoparticles (PPy-F127 NPs) with conducting and biocompatibility properties were synthesized and used to construct a L-lactic acid biosensor that could be applied in biochemical assays. The PPy-F127 NPs were characterized by transmission electron microscopy (TEM), elemental analysis and UV-vis spectroscopy. Lactate oxidase (LOx) structure variation on the PPy-F127 NPs was investigated by circular dichroism (CD). The cyclic voltammetric results indicated that LOx immobilized on the PPy-F127 NPs exhibited direct electron transfer reaction with a formal potential value (E0′) of 0.154 V vs. SCE. Moreover, the biosensor had good electrocatalytic activity toward L-lactic acid with a wide linear range (0.015–37.5 mM) and a low detection limit of 0.0088 mM. The regression equation was I (μA) = 0.02353c (mM) + 1.4135 (R2 = 0.9939). The L-lactic acid biosensor had a good anti-interference property towards uric acid (UA), ascorbic acid (AA), glucose and cysteine. The idea and method provide a promising platform for the rapid development of biosensors that can be used in the detection of biological species.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
GENE
·
2014
·
IF 2.082
Tao Wu,Anqi Guo,Qingyu Shu,Yangjian Qi,Ying Kong,Zhiping Sun,Shumin Sun,Zhengwei Fu
l -Carnitine supplementation has been used to reduce obesity caused by high-fat diet, which is beneficial for lowering blood and hepatic lipid levels, and for ameliorating fatty liver. However, whether l -carnitine may affect irregular feeding-induced obesity and lipid metabolism disorder is still largely unknown. In the present study, we developed a time-delayed pattern of eating, and investigated the effects of l -carnitine on the irregular eating induced adiposity in mice. After an experimental period of 8 weeks with l -carnitine supplementation, l -carnitine significantly inhibited body weight increase and epididymal fat weight gain induced by the time-delayed feeding. In addition, l -carnitine administration decreased levels of serum alanine aminotransferase (GPT), glutamic oxalacetic transaminase (GOT) and triglyceride (TG), which were significantly elevated by the irregular feeding. Moreover, mice supplemented with l -carnitine did not display glucose intolerance-associated hallmarks, which were found in the irregular feeding-induced obesity. Furthermore, quantitative real-time polymerase chain reaction (qRT-PCR) analysis indicated that l -carnitine counteracted the negative alterations of lipid metabolic gene expression (fatty acid synthase, 3-hydroxy-3-methyl-glutaryl coenzyme A reductase , cholesterol 7α-hydroxylase, carnitine/acylcarnitine translocase) in the liver and fat of mice caused by the irregular feeding. Therefore, our results suggest that the time-delayed pattern of eating can induce adiposity and lipid metabolic disorders , while l -carnitine supplementation might prevent these negative symptoms.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ELECTROCHIMICA ACTA
·
2013
·
IF 3.777
Zhengbo Chen,Jianwei Nai,He Ma,Zhiqiang Li
Hourglass-like nickel hydroxide nanostructure was synthesized via a simple and facile route in solution. The as-prepared nickel hydroxide nanocrystals were characterized by X-ray diffraction (XRD), scanning electronmicroscope (SEM) and transmission electron microscopy (TEM) for the morphology study. The TEM experimental data indicate that the growth of hourglass-like nanocrystal is along the c axis of β-Ni(OH) 2 . The composites had a good electron transferring and biocompatibility. The l -histidine biosensor was fabricated by drop casting the Ni(OH) 2 /ethanol solution (2.5 g L −1 ) on the surface of the glassy carbon electrode (GCE). The prepared biosensor shows better catalytic performance compared with bulk material or other similar materials, with the detection limit of 80 nM and the linear range from 0.1 μM to 0.5 mM ( R 2 = 0.993) in a 0.1 M NaOH solution. The effects of electroactive interferents at the test conditions can be negligible which showed an excellent selectivity of the biosensor. The proposed method was also successfully applied for the determination of l -histidine in human blood serum sample. High sensitivity, excellent selectivity and ease of preparation make this sensor promising for the applications in the development of detecting some other amino acids and proteins.
✓ 已验证
产品关联
DOI
高影响因子
BIOPOLYMERS
·
2013
·Vol. 101
·期 3
·210-215
·
IF 2.879
Xin Liu,Tong Chen,Yan Hu,Kexin Li,Liushui Yan
Sulfated derivatives of polysaccharide from Momordica charantia L. (MCPS) with different degree of sulfation (DS) were synthesized by chlorosulfonic acid method with ionic liquids as solvent. Fourier transform infrared spectra and 13 C nuclear magnetic resonance spectra indicated that C-6 substitution was predominant in MCPS compared with the C-2 position. Compared with the native polysaccharide from Momordica charantia L. (MCP), MCPS exhibited more excellent antioxidant activities in vitro, which indicated that sulfated modification could enhance antioxidant activities of MCP. Furthermore, high DS and moderate molecular weight could improve the antioxidant activities of polysaccharide. © 2013 Wiley Periodicals, Inc. Biopolymers 101: 210–215, 2014.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
BIOMACROMOLECULES
·
2015
·
IF 5.75
Guifei Li,Jie Wu,Bo Wang,Shifeng Yan,Kunxi Zhang,Jianxun Ding,Jingbo Yin
Self-healing polymeric hydrogels have the capability to recover their structures and functionalities upon injury, which are extremely attractive in emerging biomedical applications. This research reports a new kind of self-healing polypeptide hydrogels based on self-assembly between cholesterol (Chol)-modified triblock poly(l-glutamic acid)-block-poly(ethylene glycol)-block-poly(l-glutamic acid) ((PLGA-b-PEG-b-PLGA)-g-Chol) and β-cyclodextrin (β-CD)-modified poly(l-glutamic acid) (PLGA-g-β-CD). The hydrogel formation relied on the host and guest linkage between β-CD and Chol. This study demonstrates the influences of polymer concentration and β-CD/Chol molar ratio on viscoelastic behavior of the hydrogels. The results showed that storage modulus was highest at polymer concentration of 15% w/v and β-CD/Chol molar ratio of 1:1. The effect of the PLGA molecular weight in (PLGA-b-PEG-b-PLGA)-g-Chol on viscoelastic behavior, mechanical properties and in vitro degradation of the supramolecular hydrogels was also studied. The hydrogels showed outstanding self-healing capability and good cytocompatibility. The multilayer structure was constructed using hydrogels with self-healing ability. The developed hydrogels provide a fascinating glimpse for the applications in tissue engineering.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）