MICROCHIMICA ACTA
·
2018
·Vol. 185
·期 5
·1-9
·
IF 5.705
Yu Xinhui,Lin Yaohui,Wang Xusheng,Xu Liangjun,Wang Zongwen,Fu FengFu
An exonuclease-assisted multicolor aptasensor was developed for the visual detection of ochratoxin A (OTA). It is based on the etching of gold nanorods (AuNRs) mediated by a G-quadruplex-hemin DNAzyme. A DNA sequence (AG4-OTA) was designed that comprises a hemin aptamer and an OTA aptamer. OTA binds to AG4-OTA to form an antiparallel G-quadruplex, which halts its digestion by exonuclease I (Exo I) from the 3′-end of AG4-OTA. Thus, the retained hemin aptamer can bind to hemin to form a G-quadruplex-hemin DNAzyme. This DNAzyme has peroxidase-like activity that catalyzes the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) by H 2 O 2 to produce its diimine derivative (TMB 2+ ) in acidic solution. TMB 2+ can etch the AuNRs by oxidizing Au(0) into Au(I). This results in the generation of rainbow-like colors and provides a multicolor platform for the visual detection of OTA. The assay is based on the use of a single isolated aptamer and possesses obvious advantages such as multi-color visual inspection, relatively high sensitivity and accuracy. It can be used to detect as little as 30 nM concentrations of OTA by visual observation and even 10 nM concentrations by spectrophotometry. The method was successfully applied to the determination of OTA in spiked beer where it gave recoveries of 101–108%, with a relative standard deviation (RSD, n = 5) of <5%.
Schematic of an exonuclease-assisted multicolor bioassay based on the G-quadruplex-hemin DNAzyme-mediated etching of gold nanorods (AuNRs). It enables visual detection of ochratoxin A (OTA) with a detection limit of 30 nM.
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高影响因子
Frontiers of Chemical Science and Engineering
·
2018
·Vol. 12
·期 4
·798-805
·
IF 2.643
Duan Peizhen,Shen Juan,Zou Guohong,Xia Xu,Jin Bo
Nanorod hydroxyapatite (NRHA)/graphene oxide (GO) composites with weight ratios of 0.4, 1.5, and 5 have been fabricated by a facile ultrasonic-assisted method at room temperature and atmospheric pressure. The chemical structure properties and morphology of the composites were characterized by field emission source scanning electron microscope, X-ray diffraction, transmission electron microscopy, and high-resolution transmission electron microscopy. The results indicate that the NRHA/ GO composites have an irregular surface with different degree wrinkles and are stable, and NRHA are well combined with GO. In addition, the biomimetic mineralization mechanism of hydroxyapatite on the NRHA/GO composites in simulated body fluid (SBF) is presented. The presence of a bone-like apatite layer on the composite surface indicate that the NRHA/GO composites facilitate the nucleation and growth of hydroxyapatite crystals in SBF for biomimetic mineralization. Moreover, the NRHA- 1.5/GO composite and pure GO were cultured with MC3T3-E1 cells to investigate the proliferation and adhesion of cells. In vitro cytocompatibility evaluation demonstrated that the NRHA/GO composite can act as a good template for the growth and adhesion of cells. Therefore, the NRHA/GO composite could be applied as a GO-based, free-template, non-toxic, and bioactive composite to substitute for a damaged or defect bone.
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JOURNAL OF NANOBIOTECHNOLOGY
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2018
·Vol. 16
·期 1
·1-15
·
IF 5.294
Zhang Xiao-Shuai,Xuan Yang,Yang Xiao-Quan,Cheng Kai,Zhang Ruo-Yun,Li Cheng,Tan Fang,Cao Yuan-Cheng,Song Xian-Lin,An Jie,Hou Xiao-Lin,Zhao Yuan-Di
Background Ag 2 S has the characteristics of conventional quantum dot such as broad excitation spectrum, narrow emission spectrum, long fluorescence lifetime, strong anti-bleaching ability, and other optical properties. Moreover, since its fluorescence emission is located in the NIR-II region, has stronger penetrating ability for tissue. Ag 2 S quantum dot has strong absorption during the visible and NIR regions, it has good photothermal and photoacoustic response under certain wavelength excitation. Results 200 nm aqueous probe Ag 2 S@DSPE-PEG 2000 -FA (Ag 2 S@DP-FA) with good dispersibility and stability was prepared by coating hydrophobic Ag 2 S with the mixture of folic acid (FA) modified DSPE-PEG 2000 (DP) and other polymers, it was found the probe had good fluorescent, photoacoustic and photothermal responses, and a low cell cytotoxicity at 50 μg/mL Ag concentration. Blood biochemical analysis, liver enzyme and tissue histopathological test showed that no significant influence was observed on blood and organs within 15 days after injection of the probe. In vivo and in vitro fluorescence and photoacoustic imaging of the probe further demonstrated that the Ag 2 S@DP-FA probe had good active targeting ability for tumor. In vivo and in vitro photothermal therapy experiments confirmed that the probe also had good ability of killing tumor by photothermal. Conclusions Ag 2 S@DP-FA was a safe, integrated diagnosis and treatment probe with multi-mode imaging, photothermal therapy and active targeting ability, which had a great application prospect in the early diagnosis and treatment of tumor.
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CELLULOSE
·
2018
·Vol. 25
·期 5
·3091-3103
·
IF 3.809
Zhang Yanjuan,Wei Liping,Hu Huayu,Zhao Zengyan,Huang Zuqiang,Huang Aimin,Shen Fang,Liang Jing,Qin Yuben
Abstract Three cellulose esters, cellulose acetate-butyrate, cellulose acetate-octanoate, and cellulose acetate-laurate, were synthesized by both conventional co-reactant reaction (CCR) and mechanical activation-assisted co-reactant reaction (MACR) methods, and the corresponding nano-cellulose esters were prepared by high pressure homogenization to comparatively investigate their tribological properties as lubricant additives in liquid paraffin base oil. MACR method was more effective than CCR method for preparing long chain cellulose esters, and the MACR-prepared cellulose esters were more easily homogenized to smaller nanoparticles. Tribological testing indicated that anti-wear and load-carrying properties of the lubricants were significantly enhanced with nano-cellulose esters as additives compared to those of pure liquid paraffin, especially the MACR-prepared long chain cellulose esters. The wear scar diameter on worn surface of the steel balls reduced with the increase in degree of substitution (DS) and chain length of long chain substituents and the decrease in size dimension of nano-cellulose esters. The polar ester carbonyl groups, unesterified hydroxyl groups, and long hydrocarbon alkyl chains in nano-cellulose esters could lead to the formation of a film layer in the steel/steel contact surfaces for protecting the metals from friction and wear, which gave the lubricants with good anti-wear and load-carrying properties. The nano-cellulose esters with high DS and long chain substituents prepared by MACR technology as ecofriendly additives exhibited better lubricating ability. Graphical abstract Nano-cellulose esters with high DS of long chain substituents prepared by mechanical activation-assisted co-reactant reaction technology used as ecofriendly lubricant additives in base oil showed good anti-wear and load-carrying properties, ascribing to the formation of a film layer in the steel/steel contact surfaces for protecting the metals from friction and wear.
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MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 2
·1-8
·
IF 5.479
Li Zhentao,Mao Zhenkun,Chen Zilin
This work reports on the in-situ growth of a metal organic framework (MOF) composed of zinc(II), adeninate and biphenyldicarboxylate on the inner wall of a capillary, and the use of this MOF as a stationary phases in open-tubular capillary electrochromatography. The inner wall of a fused-silica capillary was first modified with 3-aminopropyltriethoxysilane to create surface amino sites, and then the MOF was synthesized by in-situ growth. The modified capillary was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. The results proved the successful growth of the MOF. The resultant open-tubular column showed good separation selectivity towards neutral compounds, acidic and basic compounds including nonsteroidal anti-inflammatory drugs, sulfa drugs and small biomolecules. In addition, the modified column is stable and repeatable. The precisions (expressed as RSDs) of the retention time for intra-day ( n = 5) and inter-day (n = 5) separations and between columns ( n = 3) are less than 0.5, 1.6 and 4.7%, respectively. Conceivably, this new kind of MOF represents a most useful novel stationary phase in electrochromatographic separations.
Schematic presentation of the open-tubular column modified with bio-MOF-1 by in situ hydrothermal reaction with adeninate, Zn(II) and biphenyldicarboxylate for capillary electrochromatographic separations.
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JOURNAL OF MATERIALS SCIENCE
·
2019
·Vol. 54
·期 8
·6151-6163
·
IF 3.442
Yan Dejian,Liu Jikai,Fu Xingchen,Liu Pingle,Luo He’an
Boron-rich semiconductors make significant contributions to the family of explored metal-free photocatalysts, which have attracted much attention in recent years. Boron carbide (B 4 C) belongs to a typical metal-free boron-rich photocatalyst which is facing difficulties in further optimization mainly due to the extreme conditions required for the synthesis of this material. In the present work, five different transition-metal catalysts (Fe, Co, Ni, Cu, and Zn) were investigated for lowering the crystallization temperature of B 4 C. Ni is the best catalyst for the reaction, and the crystalline mesoporous B 4 C powders can be obtained at merely 850 °C with a surface area of 130.55 m 2 g −1 , which is 27 times larger than commercial B 4 C. The photocatalytic properties of B 4 C prepared with Ni catalyst at different calcination temperatures were further evaluated by photocatalytic CO 2 reduction and generation of hydroxyl radicals. Both the crystallinity and surface area of the B 4 C would influence the final photocatalytic properties. For B 4 C photocatalysts, we firstly found that the crystallinity would influence the photogenerated holes more significantly while the surface area would have more significant influence on the photogenerated electrons. The B 4 C obtained at 950 °C exhibits the best photocatalytic activities for both CO 2 reduction and generation of ·OH radicals, which are 3.1 and 2.1 times higher than the commercial B 4 C, respectively. This present study may provide crucial references for the low-temperature synthesis of crystalline B 4 C and new opportunities for the application of the metal-free B 4 C photocatalysts to solar energy conversion.
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JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION
·
2018
·Vol. 33
·期 6
·1540-1545
·
IF 0.524
Wang Yu,Wang Youyun,Wang Wanxia,Zhu Hongda,Liu Mingxing
Colloidal mesoporous silica nanoparticles functionalized with carboxy-terminated polyethylene glycol (CMS-PEG-COOH) were successfully synthesized by covalently grafting dicarboxy-terminated polyethylene glycol (HOOC-PEG-COOH) on the surface of the amino functionalized CMS nanoparticles with amide bond as a cross linker. Moreover, the structural and particle properties of CMS-PEG-COOH were characterized by nuclear magnetic resonance spectroscopy ( 1 H-NMR), transmission electron microscopy (TEM), dynamic light scattering (DLS), nitrogen adsorption-desorption measurements, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The nanomaterials presented a relatively uniform spherical shape morphology with diameters of about 120 nm,and favorable dispersibility in weak acid solution. The CMS-PEG-COOH exhibited no changes in the state of amorphous, while the mesopores sizes of 5.25 nm might provide the nanomaterials with large capacity for the loading and releasing of drugs. So the results indicated that CMS-PEG-COOH might be a critical nanomaterial for drug delivery system in the future.
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RESEARCH ON CHEMICAL INTERMEDIATES
·
2018
·Vol. 44
·期 10
·5697-5709
·
IF 1.674
Liu Xin,Dang Li,Nai Xueying,Dong Yaping,Li Wu
Well-dispersed, high-aspect-ratio 4ZnO·B 2 O 3 ·H 2 O whiskers (4ZnO·B 2 O 3 ·H 2 O HARw ) were synthesized by a facile hydrothermal method with the aid of ZnSO 4 ·7H 2 O. The formation mechanism was investigated, and the results showed that Zn 2+ and SO
2− 4
ions played a crucial role in the control of 4ZnO·B 2 O 3 ·H 2 O HARw extended along [010] direction. X-ray diffraction (XRD) analysis, high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), and thermogravimetry (TG)-differential scanning calorimetry (DSC) results confirmed that the powder was 4ZnO·B 2 O 3 ·H 2 O. Scanning electron microscopy (SEM) and TEM showed that the average aspect ratio of the product was about 100. Nanocomposites of surface-modified 4ZnO·B 2 O 3 ·H 2 O SM-HARw /PP were prepared and their mechanical properties measured. The results suggested that the mechanical properties of 4ZnO·B 2 O 3 ·H 2 O SM-HARw /PP composites were superior to composites made with low-aspect-ratio whiskers (4ZnO·B 2 O 3 ·H 2 O SM-LARw ), which displayed poorer mechanical properties even at low addition.
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MEDICINAL CHEMISTRY RESEARCH
·
2018
·Vol. 27
·期 7
·1822-1833
·
IF 1.607
Fan Yu,Xu Yang,Han Qing-Guo,Shen Liang-Liang,Xu Hong,Wu Zhi-Bing,Xu Xu,Ying Ming,He Zhen-Dan,Hu Zhang-Li
Enzyme-activity essay demonstrated that Ligupurpuroside A acts as a natural inhibitor of lipase in a competitive manner. The inhibition mechanism and nature of lipase by Ligupurpuroside A were investigated by fluorescence spectra, UV–Vis absorption spectra, circular dichroism (CD) spectra and molecular docking methods. Fluorescence experiments indicated that Ligupurpuroside A can quench the intrinsic fluorescence of lipase through a static quenching procedure. Thermodynamic analysis suggested that hydrophobic interaction is the main force between lipase and Ligupurpuroside A. Fluorescence resonance energy transfer experiment showed that an energy transfer from lipase to Ligupurpuroside A occurs with great possibility, confirming the presence of static quenching mechanism of lipase fluorescence by Ligupurpuroside A. Interestingly, conformation of lipase remained almost the same after bound to Ligupurpuroside A based on CD spectral experiments. All these experimental results were validated by the protein-ligand docking studies which further showed that Ligupurpuroside A could bind to the amino acid residues of the hydrophobic cavity on catalytic sites of lipase. This study should be helpful for the design of diet drug and the full use of Ligupurpuroside A in food industry.
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Nano Research
·
2018
·Vol. 11
·期 6
·3272-3281
·
IF 7.994
Cai Shuangfei,Liu Xueliang,Han Qiusen,Qi Cui,Yang Rong,Wang Chen
We report a facile protocol for the one-pot preparation of monodisperse Pd nanoparticles (NPs) supported on ultrathin NiCl 2 nanosheets (NSs). The effective protocol can be described as in situ reduction–oxidation–assembly to create Pd/NiCl 2 nanocomposites and is applicable for the development of stable yet highly active Pd-based heterogeneous catalysts for organic transformations. The Pd/NiCl 2 composite displayed synergistically enhanced catalytic activity, high stability, and good recyclability for the tested model oxidation reaction. The in situ nucleation and growth of NiCl 2 NS around Pd NPs guaranteed a clean metal–support interface and greatly facilitated the catalytic reaction. This work provides a novel synthesis method for supported Pd nanocomposites suitable for many important applications.
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GLYCOCONJUGATE JOURNAL
·
2018
·Vol. 35
·期 3
·255-263
·
IF 2.548
Guo Bi-Shan,Zheng Feng,Crouch Lucy,Cai Zhi-Peng,Wang Meng,Bolam David N.,Liu Li,Voglmeir Josef
A putative GH35 β-galactosidase gene from the mucin-degrading bacterium Akkermansia muciniphila was successfully cloned and further investigated. The recombinant enzyme with the molecular mass of 74 kDa was purified to homogeneity and biochemically characterised. The optimum temperature of the enzyme was 42 °C, and the optimum pH was determined to be pH 3.5. The addition of sodium dodecyl sulphate (SDS) reduced the enzyme’s activity significantly. The addition of Mg 2+ -ions decreased the activity of the β-galactosidase, whereas other metal ions or EDTA showed no inhibitory effect. The enzyme catalysed the hydrolysis of β1,3- and β1,6- linked galactose residues from various substrates, whereas only negligible amounts of β1,4-galactose were hydrolysed. The present study describes the first functional characterisation of a β-galactosidase from this human gut symbiont.
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Nanoscale Research Letters
·
2018
·Vol. 13
·期 1
·1-8
·
IF 3.125
Yang Guo-hai,Bao Dan-dan,Zhang Da-qing,Wang Cheng,Qu Lu-lu,Li Hai-tao
Recent industrial developments and increased energy demand have resulted in significantly increased levels of environmental pollutants, which have become a serious global problem. Herein, we propose a novel all-carbon nanofiltration (NF) membrane that consists of multi-walled carbon nanotubes (MWCNTs) interposed between graphene oxide (GO) nanosheets to form a three-dimensional (3D) structure. The as-prepared membrane has abundant two-dimensional (2D) nanochannels that can physically sieve antibiotic molecules through electrostatic interaction. As a result, the prepared membrane, with a thickness of 4.26 μm, shows both a high adsorption of 99.23% for tetracycline hydrochloride (TCH) and a high water permeation of 16.12 L m − 2 h − 1 bar − 1 . In addition, the cationic dye methylene blue (MB) was also removed to an extent of 83.88%, indicating broad applications of the prepared membrane.
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