Analytical Methods
·
2014
·Vol. 6
·期 9
·2965-2972
·
IF 1.938
Qi Wang,Yun-Fei Xie,Wei-Jun Zhao,Peng Li,He Qian,Xiao-Zhi Wang
A fast and quantitative method for the detection of biogenic amines based on the microchip-based high-field asymmetric waveform ion mobility spectrometry (FAIMS) technique was established for evaluating the degree of spoilage of pork stored at room temperature. Trimethylamine (TMA) was selected as a good indicator for its volatility and high proton affinity. Analysis of standard TMA showed the same characteristic peak with the pork sample. The limit of detection of the system for TMA dissolved in deionized water, with 100 μL of 8 mol L−1 NaOH, was 3 ng and the measurement was accomplished within 15 s. The relative standard deviation (RSD) was 6.20%. The delivery of the sample gas was based on the dynamic headspace method. The effect of the storage time on the formation of biogenic amines was examined, and not surprisingly, the content of TMA increases over time. The total volatile basic nitrogen (TVB-N) was measured simultaneously based on the classical semi-micro Kjeldahl method. A good correlation coefficient between these two methods was obtained, the correlation coefficient was 0.952. Therefore the microchip-based FAIMS technique provides a quantitative classification of the spoilage or freshness of pork, especially when a rapid detection is needed.
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Analytical Methods
·
2014
·Vol. 6
·期 22
·9073-9077
·
IF 1.938
Yu Zhang,Liqian Wu,Yurong Tang,Yingying Su,Yi Lv
A new fluorescent probe for detecting lead ions (Pb2+) is reported in this work. Positively charged UCPs capped with ethylene imine polymer (PEI) and negatively charged AuNPs capped with 11-mercaptoundecanoic acid (MUA) were used as fluorescent donors and acceptors, respectively. The fluorescence quenching process was initiated by the electrostatic interaction between PEI–UCPs and MUA–AuNPs. Upon the addition of Pb2+, functionalized AuNPs were aggregated by an ion-templated chelation process, causing the departure of AuNPs from UCPs. As a result, the fluorescence of the donor was restored and the recovery was found to be proportional within the range of 0.5–10 μM to the concentration of Pb2+. The detection limit was found to be 20 nM. This method was easy to operate with satisfactory selectivity and remarkable sensitivity which would be meaningful in Pb2+-related detection.
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MICROCHIMICA ACTA
·
2014
·Vol. 181
·期 9
·1059-1067
·
IF 3.719
Zhang Zhihong,Liu Shunli,Kang Mengmeng,Yang Guang,Li Yanshan,Yan Fufeng,He Linghao,Feng Xiaozhong,Wang Peiyuan,Fang Shaoming
We report on a novel nanoarchitecture for use in highly bioactive electrochemical biosensors. It consists of multilayers of nanostructured plasma-polymerized pyrrole (ppPY) and nanosheets of electrically conductive graphene. The ppPY films were deposited by plasma-enhanced chemical vapor deposition on a graphene surface to form nanostructured composites (G-ppPY). The G-ppPY films were then coated with protein (BSA as a model) by adsorption, and then with DNA. The adsorption of protein and DNA on the nanocomposite was studied by electrochemical impedance spectroscopy and with a quartz crystal microbalance. Results demonstrated that the adsorption of biomolecules on G-ppPY films causes a higher variation in its electrochemical properties and adsorbed amount than that on a plain ppPY surface. This indicates that the presence of graphene can enhance the electrochemical activity of ppPY without reducing the sensitivity of biomolecular adsorption.
A novel nanoarchitecture is developed for use in highly bioactive electrochemical biosensors, which is composed of multilayers of nanostructured plasma-polymerized pyrrole and electrically conductive graphene nanosheets. The presence of graphene can enhance the electrochemical activity of ppPY without reducing the sensitivity of biomolecular adsorption.
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Analytical Methods
·
2014
·Vol. 6
·期 9
·2982-2987
·
IF 1.938
Hai-Jie Zhang,Yi-Hui Lu,Yi-Juan Long,Qin-Long Wang,Xiao-Xiao Huang,Rui Zhu,Xi-Liang Wang,Li-Ping Liang,Ping Teng,Hu-Zhi Zheng
Prions are a special class of pathogens that cause a number of fatal neurodegenerative diseases in mammals. This paper presents a very simple and convenient biosensor for detecting prion protein, in which a prion protein aptamer was used as the molecular recognition group and gold nanoparticles were used as the signal report group. Binding of the target molecular prion protein resulted in the enhancement of resonance light scattering (RLS) by the gold nanoparticles. A linear relationship was then identified between the enhanced RLS intensity and the concentration of prion protein in the range 0.2 to 50 nmol L−1, with a limit of detection of 0.07 nmol L−1 (3σ). The biosensor has very good selectivity for prion protein without interference by coexisting proteins, amino acids or metal ions. This “aptasensor” offers a rapid, selective and sensitive route for prion protein detection and has good potential for use in practical applications.
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Polymer Chemistry
·
2015
·Vol. 6
·期 32
·5876-5883
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IF 5.52
Yingge Shi,Meiying Liu,Ke Wang,Fengjie Deng,Qing Wan,Qiang Huang,Lihua Fu,Xiaoyong Zhang,Yen Wei
Graphene oxide (GO), as the precursor of graphene, has inspired great research interest over the past few years due to its excellent physicochemical properties and promising applications. Surface modification of GO with polymers is a general route for enhancing its processibility and improving its performance. Although great effort has been put into this field, the surface modification of GO with polymers in an aqueous solution has proven to be problematic due to the restacking of GO. In this work, we have developed a novel strategy for the preparation of GO thermo-responsive polymer nanocomposites in an aqueous solution via a combination of mussel inspired chemistry and a reversible addition–fragmentation chain transfer (RAFT) polymerization. Two simple steps are involved in this strategy. First, GO was coated with polydopamine (PDA) through a self polymerization of dopamine in a weakly alkaline aqueous solution. Then, the thermo-sensitive polymer poly(N-isopropylacrylamide) (PNIPAM), derived from a polymerization, was facilely grafted onto the PDA coated GO (GO-PDA) through a Michael addition reaction. The finally product (GO-PDA-PNIPAM) was characterized in detail by a series of methods, including Fourier transform infrared spectroscopy, thermal gravimetric analysis, transmission electron microscopy and X-ray photoelectron spectroscopy. These results suggested that PNIPAM can successfully and effectively functionalize GO through a rather facile strategy in an aqueous solution, at room temperature and in an air atmosphere. More importantly, GO-PDA-PNIPAM exhibited excellent dispersibility in aqueous solutions and some organic media, and displayed a good thermo-responsiveness. Taking advantage of PDA and polymerizations, this strategy is expected to be extended for the preparation of many other polymer nanocomposites by employing different nanomaterials and monomers. Therefore, the strategy described in this work should be of great research interest for the preparation and applications of nanocomposites.
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Soft Matter
·
2013
·Vol. 9
·期 46
·11136-11142
·
IF 3.909
Jingjun Wu,Qian Zhao,Chengzhen Liang,Tao Xie
Enzyme-degradable hydrogels with aligned pores were prepared via unidirectional freezing of a mixed solution of oxidized dextran (oxDex) and chitosan (CHI) followed by cryo-gelation. At the frozen state, imine bonds as the crosslinking points of the hydrogels were formed as a result of the reaction between the aldehyde groups on the oxDex and the amino groups on the CHI. The morphologies of the obtained hydrogels were studied by confocal laser scanning microscopy (CLSM). Microtubular pores aligned along the freezing direction were obtained in the swollen state of the hydrogels. The pore size was adjustable ranging from 20 to 100 μm by controlling the freezing temperature in the unidirectional freezing step. Upon exposure of the hydrogels to chitosanase solution, chitosan can be hydrolyzed into short oligosaccharide fragments leading to collapse and degradation of the gel network. The degradation rate can be tuned by adjusting the gel composition and enzyme concentration.
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PLoS One
·
2015
·Vol. 10
·期 4
·e0121817
·
IF 3.234
Huiying Chen,Shaohui Cui,Yinan Zhao,Chuanmin Zhang,Shubiao Zhang,Xiaojun Peng
Modifying chitosan (CS) with polyethylenimine (PEI) grafts is an effective way to improve its gene transfection performance. However, it is still a challenge to conduct the grafting with fine control and high efficiency, particularly for the modification of water-insoluble CS. Herein, a novel method to graft CS with PEI (1.8 kDa, PEI-1.8) was developed by using ionic liquid 1-butyl-3-methyl imidazolium acetate ([BMIM]Ac) as a reaction solvent, water-insoluble CS as a reaction substrate and 1,1-carbonyldiimidazole (CDI) as a linking agent. The grafting reaction was greatly accelerated and the reaction time was largely shortened to 4 h by taking advantages of the good solubility of CS, the enhanced nucleophilicity of amino groups and the preferential stability of the activated complexes in the ionic liquid. The chitosan- graft -polyethylenimine (CS- g -PEI) products were characterized by 1 H NMR, FTIR and GPC. PEI-1.8 was quantitatively grafted to CS through urea linkages, and the grafting degree (GD) was conveniently tuned by varying the molar ratios of PEI-1.8 to D-glucosamine units of CS in the range of 9.0 × 10 -3 to 9.0 × 10 -2 . Compared with CS, the synthesized CS- g -PEI copolymers showed higher pDNA-binding affinity, which increased with the GD as shown in Agarose gel electrophoresis. The dynamic light scattering (DLS) experiment demonstrated that the CS- g -PEI/pDNA polyplexes had suitable particle sizes and proper ζ-potentials for cell transfection. The CS- g -PEI copolymer with a medium GD of 4.5% conferred the best gene transfection, with the efficiency 44 times of CS and 38 times of PEI-1.8 in HEp-2 cells. The cytotoxicity of CS- g -PEI was tested and found nearly as low as that of CS and much lower than that of PEI.
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PubMed
高影响因子
Journal of Environmental Sciences
·
2015
·
IF 2.002
Manke Jia,Xiaolong Hu,Shulian Wang,Yingping Huang,Lirong Song
In this study, bismuth oxyhalide (BiOXs (X Cl, Br, I)) semiconductors were prepared by a simple solvothermal method, with ethanol serving as solvent and a series of tetrabutylammonium halide surfactants as halogen sources. Under identical synthetic conditions, BiOBr was more readily constructed into regular flower-like hierarchical architectures. The photocatalytic properties of the materials were studied by monitoring the degradation of rhodamine B (RhB), with visible light absorption , and colorless salicylic acid (SA). It was found that both RhB and SA were rapidly degraded on the surface of BiOBr. BiOCl was rather active for the degradation of RhB, but ineffective toward the degradation of SA. However, neither RhB nor SA could be degraded effectively in the case of BiOI. Further experiments such as UV–visible spectroscopy and detection of OH and O 2 − radicals suggest that the electronic structure of the BiOX photocatalysts is responsible for the difference in their activities.
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RSC Advances
·
2015
·Vol. 5
·期 75
·61436-61439
·
IF 3.84
Nan Li,Yong Shen,Li Qi,Zhibo Li,Juan Qiao,Yi Chen
A versatile method for preparing a reverse phase/weak anion exchange/hydrophilic interaction trimodal polymer monolith was proposed by the one-step copolymerization of amino acid-based monomer and N,N′-methylenebisacrylamide. The retention mechanisms of the resultant monolith were evaluated using different series of small molecules. Furthermore, the separation of protein mixtures could be easily achieved under isocratic elution. The proposed polymer monolith, which has the merits of easy preparation, low mass transfer resistance and good biocompatibility, is a promising separation medium for small and large molecules.
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ELECTROCHIMICA ACTA
·
2016
·
IF 4.803
Junfang Cheng,Ming Zhang,Yuexing Jiang,Lu Zou,Yingpeng Gong,Bo Chi,Jian Pu,Li Jian
Non-aqueous lithium air batteries with high energy density have been regarded to be the most attractive contender in the future energy storage techniques. Herein, the perovskite La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 (LSCF) nanoparticles are studied as the cathode catalyst for non-aqueous lithium air batteries. The results confirm that nanostructured LSCF exhibits admirable electrochemical activity and can effectively reduce the overpotential. Batteries with LSCF catalyst can increase the discharge capacity from 9678 mAh g −1 to 13979 mAh g −1 and improve the cycle stability from 10 cycles to 20 cycles at 200 mA g −1 . The study reveals that the formation and decomposition processes of Li 2 O 2 can be effectively promoted by the introduction of LSCF nanoparticles. The possible catalytic mechanism of LSCF in reducing overpotential is also proposed.
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ACS Applied Materials & Interfaces
·
2014
·
IF 5.9
Xiaofei Wang,Ding Zhu,Ming Song,Shengrong Cai,Lei Zhang,Yungui Chen
The “(−) lithium (Li) anode|organic anolyte + inorganic catholyte|solid-state cathode (+)” Li–O2/air battery based on an inorganic solid-state air cathode was fabricated with a simple method. The electrochemical performance and reaction products of the Li–O2/air batteries under pure O2 and ambient air were investigated, respectively. The inorganic Li-ion conductive solid-state electrolyte Li1.3Al0.3Ti1.7(PO4)3 was stable during cycling and avoided the decomposition and volatilization problems that conventional organic electrolytes faced. Moreover, the porous air cathode provided a sufficient gas-phase O2-transport channel, facilitating the achievement of a high capacity of 14192 or 7869 mA h g–1 under pure O2 or ambient air, respectively. Our results demonstrate that the Li–O2/air battery using an inorganic porous air cathode has a great potential for practical application.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2017
·
IF 5.401
Ningning Zhou,Guowen Meng,Chuhong Zhu,Bin Chen,Qitao Zhou,Yan Ke,Dexian Huo
A silver film is in situ grafted on a melamine sponge via the silver mirror reaction. The porous structure of the sponge possesses an enlarged total SERS-active surface area without increasing the overall footprint of the SERS substrate. The Ag-grafted sponge exhibits high SERS activity toward Rhodamine 6G with a concentration down to 0.1 pM. Moreover, the sponge-based substrate also offers a good signal uniformity and reproducibility with a relative signal deviation down to 11.7% and 13.2%, respectively. Furthermore, the Ag-grafted sponge exhibits a limit of detection of 4.23 nM toward adenine and 1.88 nM toward thiram in the aqueous solution by a handheld portable Raman spectrometer. The inexpensive and simple Ag-grafted sponge can be used as an effective SERS substrate, which will find the potential application in field-deployable detection of organic pollutants in the aquatic environment.
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