COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2014
·
IF 2.354
Tianqi Li,Haihui Zhou,Jiaqi Huang,Junli Yin,Zhongxue Chen,Dan Liu,Ningshuang Zhang,Yafei Kuang
Pd–Au bimetallic nanoparticles were facilely prepared on Ni foil substrate via in-situ self-assembly in reverse microemulsion of water/Triton X-100/n-hexanol/n-hexane. The Pd–Au nanomaterials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). A homogeneous alloy structure of Pd–Au in the bimetallic nanoparticles is indicated by XRD analysis and TEM. The SEM results show that the resultant bimetallic nanoparticles disperse uniformly on Ni foil with a narrow size distribution. The apparent size of bimetallic nanoparticles deposited on Ni depends on the reaction time of self-assembly. The TEM results reveal that the Pd–Au bimetallic nanoparticles consist of smaller homogeneous alloy nanoparticles with an average diameter of 5.1 nm, size of which depends on the size of micro water droplets. The growth mechanism of the Pd–Au nanoparticles in microemulsion was also explored. The electrocatalytic performance of the Pd–Au NPs/Ni electrode was studied by cyclic voltammetric and chronoamperometric measurements. Electrochemical experiments show that the Pd–Au nanoparticles have good catalytic activity and good stability for ethanol oxidation in alkaline media.
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ANALYST
·
2014
·Vol. 139
·期 21
·5482-5487
·
IF 3.906
Hanping He,Xiaoqian Peng,Min Huang,Gang Chang,Xiuhua Zhang,Shengfu Wang
A small molecule modified sensor was developed for the detection of XGG trinucleotide repeats (X = C, T) by electrochemical impedance spectroscopy. The sensor (NCD/MPA/Au) was fabricated by immobilizing the nucleic acid recognition molecule (NCD) on the surface of a gold electrode through a condensation reaction between the amino-terminal end of the NCD linker and carboxylic groups in 3-mercaptopropionic acid that were self-assembled on the electrode surface. After the sensor was incubated with trinucleotide repeats, electrochemical impedance spectroscopy was performed using [Fe(CN)6]3−/4− as redox marker ions. XGG repeats (X = C, T) could be selectively detected based on the differences in charge transfer resistance (ΔRct) even in the presence of other trinucleotide repeats. The relationship between ΔRct and lg [concentration of CGG repeats] for the sensor was linear from 1 nM to 1 μM, enabling the quantification of the number of repeats. The electrochemical impedance sensor provides a simple and rapid method to detect trinucleotide repeats without requiring labelling and immobilizations of DNA, making it promising for the early diagnosis of neurodegenerative diseases; the sensor may be further extended to the detection of other special sequences of DNA.
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BIOSENSORS & BIOELECTRONICS
·
2014
·
IF 6.451
Qi Zhang,Xiaojun Chen,Fulai Tu,Cheng Yao
The measurement of free thyroxine concentration in serum is considered to be an essential indicator of thyroid function . Here, a novel enzyme-free sandwich electrochemical immunosensor for the detection of FT4 antigen based on the immobilization of primary antibody (Ab 1 ) on three dimensional ordered macroporous chitosan–Au nanoparticles hybrid (3DOM CS–AuNPs) film electrode, and magnetic multiwall carbon nanotubes (MMWCNTs) were used as label of secondary antibody (Ab 2 ). The 3DOM CS–AuNPs film electrode was constructed by one-step electrodeposition of CS–AuNPs composite onto Au electrode with silica opal template. MMWCNTs were prepared by chemical co-precipitation of Fe 2+ and Fe 3+ salts on carboxylated MWCNTs. Ru(bpy) 3 2+ labeled anti-FT4 (Ru(bpy) 3 2+ –Ab 2 ) was covalently attached to MMWCNTs through the formation of amide bond between the carboxylic groups of MWCNTs and the amine groups of antibody. Under the optimal conditions, FT4 was detected in a concentration range from 0.71 fg mL −1 to 1.15 pg mL −1 with a correlation coefficient of 0.998 and a detection limit of 0.20 fg mL −1 . Moreover, the immunosensor showed excellent selectivity, good stability, satisfactory reproducibility and regeneration. Importantly, the developed method was used to assay clinical serum specimens, achieving a good relation with those obtained from the commercialized electrochemiluminescent method.
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ACS Catalysis
·
2015
·
IF 9.312
Jingyi Hu,Qiwei Yang,Lifeng Yang,Zhiguo Zhang,Baogen Su,Zongbi Bao,Qilong Ren,Huabin Xing,Sheng Dai
Metal catalysts often encounter the dilemma of rapid deactivation due to reduction or particle aggregation/growth during the reaction. Here we reported an active and stable metal nanoparticles (NPs)/surfactant ionic liquid (IL) system for the catalytic hydrochlorination of acetylene. The NPs of Pd, Au, and Pt with a narrow size distribution and well-defined lattice fringes experienced in situ generation in the reaction medium of anionic surfactant carboxylate ILs (ASC-ILs). Benefiting from the high reactivity of NPs and the self-assembly property of ASC-ILs, an effective redox cycle between Pd0 and PdII was established to reduce the deactivation of metal catalysts. The Pd NPs/surfactant IL systems showed excellent catalytic activity toward acetylene hydrochlorination. An acetylene conversion of 93% and a selectivity of 99.5% were achieved with no discernible deterioration over a reaction time of 55 h. Furthermore, ASC-ILs were endowed with a unique property of the strong hydrogen-bond basicity, which was effective in absorbing and activating acetylene and HCl. This study manifests that metal NPs/surfactant IL systems are promising as substitutes for toxic mercury catalysts in the hydrochlorination of acetylene, and also is instructive for the stabilization of metal NPs.
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SENSORS AND ACTUATORS B-CHEMICAL
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2015
·
IF 4.097
Hong Huang,Hua Li,Jiu-Ju Feng,Ai-Jun Wang
Herein, we demonstrate a facile, straightforward and green method for synthesis of highly red-emitting fluorescent bimetallic Au/Ag nanoclusters (NCs) employing lipoic acid as both a reducing agent and a protecting agent. The as-prepared Au/Ag NCs exhibited bright red emission with a strong peak centered at 630 nm (quantum yield measured as 6.4%), and showed excellent stability and remarkable temperature-dependent fluorescent property. The fluorescence responses were reversible and linear to the environment temperature from 20 to 65 °C with a resolution as high as 1.34 °C, which allows its potential application as a fluorescent nanothermometer. Moreover, Au/Ag NCs were also explored for selective and sensitive determination of Fe 3+ based on the specific quenching of the fluorescence by Fe 3+ , and explored for fluorescence imaging Fe 3+ in living HeLa cells thanks to their very low cytotoxicity.
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Nano Research
·
2016
·Vol. 9
·期 3
·876-885
·
IF 8.893
Qian Hongmei,Xu Meng,Li Xiaowei,Ji Muwei,Cheng Lei,Shoaib Anwer,Liu Jiajia,Jiang Lan,Zhu Hesun,Zhang Jiatao
This study reports the controllable surface roughening of Au–Ag alloy nanoplates via the galvanic replacement reaction between single-crystalline triangular Ag nanoplates and HAuCl 4 in an aqueous medium. With a combination of experimental evidence and finite element method (FEM) simulations, improved electromagnetic field (E-field) enhancement around the surface-roughened Au–Ag nanoplates and tunable light absorption in the near-infrared (NIR) region (~800–1,400 nm) are achieved by the synergistic effects of the localized surface plasmon resonance (LSPR) from the maintained triangular shape, the controllable Au–Ag alloy composition, and the increased surface roughness. The NIR light extinction enables an active photothermal effect as well as a high photothermal conversion efficiency (78.5%). The well-maintained triangular shape, surface-roughened evolutions of both micro- and nanostructures, and tunable NIR surface plasmon resonance effect enable potential applications of the Au–Ag alloy nanoplates in surface-enhanced Raman spectroscopic detection of biomolecules through 785-nm laser excitation.
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JOURNAL OF NANOPARTICLE RESEARCH
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2015
·Vol. 17
·期 12
·1-11
·
IF 2.184
Song Ji-Tao,Yang Xiao-Quan,Zhang Xiao-Shuai,Yan Dong-Mei,Yao Ming-Hao,Qin Meng-Yao,Zhao Yuan-Di
In this study, composite nanoparticles comprising Au nanoparticle and quantum dots were built and used for contrast-enhanced computed tomography imaging (CT) and fluorescence dual-mode imaging in vivo. The nanoparticle exhibited good monodispersity and good biocompatibility, and had excellent CT contrast-enhancement effect and fluorescence imaging capability. They were appropriate for being used as dual-mode imaging probe in vivo.
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WATER RESEARCH
·
2014
·
IF 5.323
Yiming Su,Adeyemi S. Adeleye,Yuxiong Huang,Xiaoya Sun,Chaomeng Dai,Xuefei Zhou,Yalei Zhang,Arturo A. Keller
Nanoscale zerovalent iron (nZVI) has demonstrated high efficacy for treating nitrate or cadmium (Cd) contamination, but its efficiency for simultaneous removal of nitrate and Cd has not been investigated. This study evaluated the reactivity of nZVI to the co-contaminants and by-product formation, employed different catalysts to reduce nitrite yield from nitrate, and examined the transformation of nZVI after reaction. Nitrate reduction resulted in high solution pH, negatively charged surface of nZVI, formation of Fe 3 O 4 (a stable transformation of nZVI), and no release of ionic iron. Increased pH and negative charge contributed to significant increase in Cd(II) removal capacity (from 40 mg/g to 188 mg/g) with nitrate present. In addition, nitrate reduction by nZVI could be catalyzed by Cd(II): while 30% of nitrate was reduced by nZVI within 2 h in the absence of Cd(II), complete nitrate reduction was observed in the presence of 40 mg-Cd/L due to the formation of Cd islands (Cd(0) and CdO) on the nZVI particles. While nitrate was reduced mostly to ammonium when Cd(II) was not present or at Cd(II) concentrations ≥ 40 mg/L, up to 20% of the initial nitrate was reduced to nitrite at Cd(II) concentrations < 40 mg/L. Among nZVI particles doped with 1 wt. % Cu, Ag, or Au, nZVI deposited with 1 wt. % Au reduced nitrite yield to less than 3% of the initial nitrate, while maintaining a high Cd(II) removal capacity.
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ELECTROCHIMICA ACTA
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2014
·
IF 4.086
Jing-Jing Lv,Shan-Shan Li,Ai-Jun Wang,Li-Ping Mei,Jian-Rong Chen,Jiu-Ju Feng
In this work, a simple and facile strategy was developed for preparation of well-defined Au-Pd bimetallic alloyed nanoparticles uniformly supported on reduced graphene oxide nanosheets (RGOs) under solvothermal conditions. The detailed morphology, crystal structure, and composition were well characterized by (high-resolution) transmission electron microscopy (TEM), X–ray diffraction (XRD), and X–ray photoelectron spectroscopy (XPS). The as-prepared nanocomposites displayed the enhanced catalytic ability, better stability, and good methanol tolerance towards oxygen reduction reaction (ORR) in alkaline media, compared with commercial Pd black and RGOs (reduced by NaBH 4 ) catalysts. The as-developed method could be applied for synthesis of other morphology-controlled bimetallic electrocatalysts.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2017
·
IF 5.401
Xiange Peng,Gengping Wan,Lihong Wu,Min Zeng,Shiwei Lin,Guizhen Wang
The exploitation of multifunctional nanomaterials used for colorimetric biosensing assays is highly desired in diagnostic applications. In this paper, a novel TiO 2 -encapsulated Au ( [email protected] 2 ) yolk-shell nanostructure was synthesized via a simple and controllable method, in which the TiO 2 nanotubes could effectively restrain the aggregation and growth of Au nanoparticles and supply more active sites and high surface areas for biocatalytic reactions. The microstructure and composition of as-prepared nanocomposites were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution TEM (HRTEM), and X-ray photoelectron spectroscopy (XPS). The results demonstrated that unique [email protected] 2 yolk-shell nanostructure with the well-dispersed Au nanoparticles confined in nanotube was obtained. The investigation of peroxidase-like activity of [email protected] 2 nanocomposites confirmed that the relative catalytic kinetic followed Michaelis–Menten behaviors. On the basis of the highly efficient peroxidase-like activity of [email protected] 2 , an effective method for colorimetric detection of H 2 O 2 and glucose was established. Considering numerous advantages including reduced aggregation, good chemical stability and high catalytic activity available by the present [email protected] 2 with unique structure, designing other yolk-shell nanostructures with exact function orientation using a similar strategy may also be very promising in the application of biocatalysis and bioassays.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2017
·
IF 2.843
Hai Liu,Ting Lian,Yang Liu,Yingling Hong,Daohua Sun,Qingbiao Li
In order to investigate the roles of active molecules during the bioinspired synthesis process of gold nanoparticles by Cacumen platycladi leaf extract, flash column chromatography was employed to separate the Cacumen platycladi leaf extract according to the polarity differences. Fourier transform infrared spectroscopy and high-performance liquid chromatography equipped with a photodiode array detector were adopted to identify the category of the isolated samples. The results have demonstrated that components in the Cacumen platycladi leaf extract can be sorted into three categories: sugars (the Sloading and S0), polyphenols (S1∼S5), and flavonoids (S6∼S8). The characterizations of gold nanoparticles, produced by each isolated sample with chloroauric acid, indicate the strong-to-weak sequence of reducing power is polyphenols, flavonoids, and sugars. Sugars have no protection strength for the biosynthesis of gold nanoparticles, polyphenols involved in isotropous stabilization, while flavonoids are responsible for the anisotropic growth.
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RSC Advances
·
2016
·Vol. 6
·期 23
·19620-19625
·
IF 3.289
Simin Lu,Ling Chen,Ping Yang,Katarzyna Matras-Postolek
The detection of catalase associated with various diseases is very important due to the fact that it is frequently downregulated in human cancer tissues. Noble metal nanomaterial-assisted sensors have achieved rapid development for wide applications but few for detecting catalase. Thus, a novel colourimetric strategy has been developed for the selective and rapid visual detection of catalase by using the decelerating etching of gold nanorods (NRs). In the presence of hexadecyltrimethylammonium bromide and SCN−, which can reduce the redox potential of Au(I)/Au (0), Au NRs would be etched by H2O2 along the longitudinal direction. As a consequence, the colour of solutions changed from bluish green to pink accompanied by the localized surface plasmon resonance (LSPR) extinction peak being shifted to short wavelength. In contrast, the etching process would be prohibited in the presence of catalase, and the colour and LSPR extinction peak of Au NRs would remain unchanged. Furthermore, this Au NR based sensor is applied to test paper that could be used in the detection of catalase in real samples. The discussion of the mechanism indicates that such a sensing method has an ideal performance in terms of sensitivity, selectivity, and linearity.
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