SENSORS AND ACTUATORS B-CHEMICAL
·
2016
·
IF 4.758
Yuan Zhou,Zhanfang Ma
Pursuing for a simple, sensitive and inexpensive method of detecting copper ions is very essential for both environment and human health. Herein, a new strategy for fluorescence detection of Cu 2+ was designed which is based on the reduction of Cu 2+ to Cu + by sodium ascorbate to get cycloaddition reaction between 4-azidobenzoic acid-tagged Au@SiO 2 and propiolic acid-tagged carbon dots (CDs). The proposed approach not only possesses a good selectivity, but also has a linear relationship between the fluorescence intensity and the concentrations of Cu 2+ in the range of 0.1–100 nM with the detection limit of 0.08 nM (5.12 × 10 −9 mg mL −1 ), which is far below the limit value of 1.3 mg mL −1 defined by U.S. Environmental Protection Agency in drinkable water. In the actual sample, the standard deviation ranges from 97.6% to 101.8%, indicating the high precision of present approach.
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高影响因子
ELECTROANALYSIS
·
2016
·Vol. 29
·期 2
·602-608
·
IF 2.471
Zhiming Jiang,Qin Liu,Yuran Tang,Mingxiao Zhang
Pt−Au nanoclusters decorated on the surface of reduced graphene oxide (rGO/Pt−Au) was facilely prepared by one-pot electrochemical reduction. The morphology and composition of rGO/Pt−Au composites had been characterized by scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectrometry (EDX), fourier transform-infrared spectroscopy (FT-IR) and electrochemical methods. Ofloxacin is a member of synthetic quinolones which has been widely used for the treatment of common diseases in humans and animals. The performance of the rGO/Pt−Au nanocomposite toward the oxidation of ofloxacin was compared with the other similar nanostructures like rGO/Pt and rGO/Au. In the optimized conditions, two linear calibration curves were obtained, from 0.08 to 10 μM and 10 to 100 μM ofloxacin. A detection limit of 0.05 μM ofloxacin was observed at pH 5.7 for the GCE/rGO/Pt−Au. The proposed sensor was successfully applied to determine ofloxacin in tablets and human urine samples and the results were satisfactory.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2017
·
IF 4.233
Huilin Li,Dandan Men,Yiqiang Sun,Dilong Liu,Xinyang Li,Liangbin Li,Cuncheng Li,Weiping Cai,Yue Li
We developed an interesting route for preparing a poly (acrylamide- co -acrylic acid) (P(AAm- co -AA)) hydrogel microsphere with a coating of Au nanospheres (hydrogel microsphere @ Au nanospheres) through self-assembly based on electrostatic interaction. The fabricated composites could be used as highly sensitive enhanced Raman scattering substrates. The nanogaps between adjacent Au nanospheres were dynamically tuned by volume changes in the hydrogel microspheres in the semiwet state under different pH conditions. At pH 6, the hydrogel microsphere @ Au nanospheres demonstrated highly sensitive SERS with an enhancement factor of 10 9 . The product could detect very low concentrations of analytes up to 10 −12 M 4-aminothiophenol (4-ATP) molecules. This paper proposes a new method for detecting trace amounts of environmental organic pollutants by dynamically tuning the SERS enhancement in the semiwet testing state.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2017
·
IF 6.216
Yidi Wang,Bowen Li,Guanshu Li,Xue Ma,Hongbo Zhang,Yingying Huang,Guowei Wang,Jun Wang,Youtao Song
Z-scheme structure is an effectively construction to improve the photocatalytic activity due to the excellent photo-generated electron-hole pairs separation efficiency. In this paper, the Er 3+ :YAlO 3 @(PdS/BiPO 4 )/(Au/rGO), (Au/rGO)/CdS and modified Z-scheme Er 3+ :YAlO 3 @(PdS/BiPO 4 )/(Au/rGO)/CdS photocatalysts were prepared by hydrothermal, ultrasonic dispersion, deposition-precipitation and ultrasonic-assisted methods. The prepared samples were characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectra (DRS), fourier transform infrared spectra (FT-IR), raman spectra and photoluminescence (PL) spectra. The photocatalytic activity of prepared samples were evaluated via photocatalytic conversion rate of nitrite under ultraviolet-light and simulated solar-light irradiations. Due to the enhanced separation efficiency of electron-hole pairs, the Er 3+ :YAlO 3 @(PdS/BiPO 4 )/(Au/rGO)/CdS exhibited excellent performance under both ultraviolet-light and simulated solar-light irradiation, reaching 94.59% and 91.25% conversion rates, respectively. Meanwhile, the effects of simulated solar-light irradiation time and corresponding reaction kinetics on photocatalytic conversion of nitrite were studied. Subsequently, the effects of electron and hole scavengers were investigated to further elaborate the possible mechanism. In addition, the study of used times showed that the prepared modified Z-scheme Er 3+ :YAlO 3 @(PdS/BiPO 4 )/(Au/rGO)/CdS nanocomposites can be effectively recycled without an apparent inactivation on photocatalytic activity. This research may provide a potential way by utilizing solar energy efficiently for converting nitrite and other contaminants released into the environment.
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ELECTROCHIMICA ACTA
·
2016
·
IF 4.803
Zhen Liu,Jingkun Xu,Ruirui Yue,Taotao Yang,Lei Gao
This paper demonstrates that Au–PEDOT/reduced graphene oxide nanocomposite (Au–PEDOT/rGO) can be rapidly synthesized through a facile, cost-effective one-pot method with chloroauric acid as the oxidant and NaBH 4 as the reductant successively. The morphology, composition and structure of the obtained composites were confirmed by SEM, TEM, XRD, Raman and XPS characterizations. The Au–PEDOT/rGO modified glassy carbon electrode (GCE) showed significantly improved charge transfer efficiency and high electrocatalytic activity toward caffeic acid (CA) oxidation as compared to bare GCE and Au-PEDOT modified electrode. Under optimized conditions, the Au–PEDOT/rGO constructed sensors exhibited a wide linear range of 0.01–46 μM with the correlation coefficient of 0.9926 and a detection limit as low as 0.004 μM for the detection of CA. To validate its possible application, the present sensor was also illustrated with satisfactory anti-interference performance, high reproducibility and sensitivity for the determination of CA in red wine sample. The prepared Au–PEDOT/rGO nanocomposite is a promising electrode material for the determination of CA in red wines or other CA-containing food and beverage.
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Analytical Methods
·
2016
·Vol. 8
·期 9
·2097-2105
·
IF 1.915
Junrong Li,Liang Lv,Guannan Zhang,Xiaodong Zhou,Aiguo Shen,Jiming Hu
We herein present a simple and surfactant-free synthetic strategy for the preparation of core–shell Fructus Broussonetia-like Au@Ag@Pt nanoparticles (FBNPs) via a combination of galvanic replacement and reagent reduction, in which a chitosan (CS)-mediated epitaxial growth of Pt multi-branches occurs on cresyl violet labeled Au core–Ag shell nanoparticles (NPs) at room temperature. The as-prepared novel nanostructures exhibit an enzyme mimetic activity due to the formation of a Fructus Broussonetia-shaped Pt shell, the absence of surfactants and the positively charged CS molecules intertwined within the outermost Pt NPs. Relying on the high sensitivity of resonance-enhanced Raman scattering and the highly efficient intrinsic peroxidase-like activity of FBNPs, H2O2 was detected with a wide detection window from 10 pM to 100 μM when utilizing 3,3′,5,5′-tetramethylbenzidine (TMB) as the substrate. Based on the H2O2–TMB catalytic oxidation system a simple, sensitive, selective and universal platform has been extended for the detection of all peroxidase-related analytes. For example, glucose at a concentration range of 1 nM to 200 μM was detected in the presence of glucose oxidase with a limit of detection of 1 nM.
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PARTICLE & PARTICLE SYSTEMS CHARACTERIZATION
·
2016
·Vol. 33
·期 4
·212-220
·
IF 4.367
Mei Lei,Wei Wu,Shuanglei Yang,Xingang Zhang,Zhuo Xing,Feng Ren,Xiangheng Xiao,Changzhong Jiang
The reduction of 4-nitrophenol (Nip) into 4-aminophenol (Amp) by NaBH 4 , which is catalyzed by both binary and ternary yolk–shell noble-metal/SnO 2 heterostructures, is reported. The binary heterostructures contain individual Au or Ag nanoparticles (NPs) and the ternary heterostructures contain both Au and Ag NPs. The Au@SnO 2 yolk–shell NPs are synthesized via a silica seeds-mediated hydrothermal method. Subsequently, the Au@SnO 2 @Ag and Au@SnO 2 @Au yolk–shell–shell (YSS) NPs are synthesized, whereby SnO 2 is located between the Au and Ag NPs. The morphology, composition, and optical properties of the as-prepared samples are analyzed. For the binary heterostructures, the rate of the reduction reaction increases with decreasing particle size. The catalytic results demonstrate the synergistic effect of Au and Ag in the ternary metal–semiconductor heterostructures, which is beneficial to the catalytic reduction of Nip into Amp. Both the binary and ternary heterostructures exhibit significantly better catalytic performances than the corresponding bare Au and Ag NPs. It is envisaged that the current synthesized strategy will promote further interest in the field of bimetal NP-based catalysis.
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RSC Advances
·
2016
·Vol. 6
·期 61
·55878-55883
·
IF 3.289
Jinxing Chen,Feng Chen,Yiyao Wang,Mozhen Wang,Qichao Wu,Xiao Zhou,Xuewu Ge
A sub-micron sized highly-crosslinked poly(ethyleneglycol dimethacrylate) (PEGDMA) microsphere supported nano-Au catalyst (PEGDMA@AuNP) was successfully prepared through a one-step synthesis method at room temperature and ambient pressure, taking advantage of the γ-ray radiation effect on a simple one-pot system, i.e. a methanol–water solution containing EGDMA, 4-VP, and HAuCl4. Electron microscopy, XPS, and XRD analyses proved that AuNPs of several nanometers had been synthesized and loaded simultaneously with the formation of crosslinked PEGDMA microspheres when the adsorbed dose rate and the initial concentration of HAuCl4 were controlled within a narrow range, i.e. 35–80 Gy min−1 and below 1 mmol L−1 of [HAuCl4]. The size of the prepared PEGDMA@AuNP microspheres changed little with the dose rate, but decreased with the initial [HAuCl4], from 900 nm at 0.1 mmol L−1 to 680 nm at 1 mmol L−1. At the same time, the size of AuNPs increases with the initial [HAuCl4], from 8 nm at 0.1 mmol L−1 to 35 nm at 1 mmol L−1. The prepared PEGDMA@AuNP microspheres can be dispersed stably in both water and organic solvent, CH3CN. They exhibit excellent catalytic efficiency not only on the reduction of Fe(CN)63− by NaBH4 in aqueous solution, but also on the cis–trans isomerization of azobenzenes in CH3CN at room temperature. A satisfactory repeatability of the catalytic performance of the prepared PEGDMA@AuNP microspheres was achieved in organic solvents. This work opens a new green simple and economic way to the synthesis of efficient and chemically-stable polymer-supported nano-metal catalysts.
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高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2016
·
IF 2.628
Xinping Duan,Yan Yin,Xuelin Tian,Jinhuo Ke,Zhaojun Wen,Jianwei Zheng,Menglin Hu,Linmin Ye,Youzhu Yuan
Disintegration or redispersion of supported sintered gold nanoparticles (Au NPs) in the presence of alkyl halide can give catalyst regeneration or redispersion of sintered Au catalysts. The selectivity of alkyl halides, temperature and size distributions were investigated to elucidate the redispersion of Au NPs during halide-induced decomposition. This study proved that the alkyl halide induced the redispersion of sintered Au NPs which depended on the R–X (X = I, Br, Cl) bond dissociation energy (BDE) and thus provided a simple descriptor for the regeneration of inactive supported Au catalysts. A correlation between the BDE of R–X and dispersion efficiency was established. The tendency for disintegration and redispersion followed the R–X BDE of the alkyl halide. Compared to alkyl chlorides and bromides, iodides were more efficient for redispersing sintered Au NPs. As a descriptor, the BDE of R–I played a crucial role in particle redispersion. These findings provided insights into the mechanism of organic halide-induced Au NP disintegration and the effect of the halide type on the redispersion of sintered catalysts.
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BIOSENSORS & BIOELECTRONICS
·
2017
·
IF 7.78
Shuai Chen,Pin Liu,Kewen Su,Xuan Li,Zhen Qin,Wei Xu,Jun Chen,Chaorui Li,Jingfu Qiu
In this work, novel octahedral Cu 2 O-Au nanocomposites were synthesized and first applied in an electrochemical aptasensor to detect thrombin (TB) with the aid of a DNAzyme for signal amplification . The octahedral Cu 2 O-Au nanocomposites have not only simultaneously served as signal amplifying molecules but have also been utilized as an ideal loading platform to immobilize a large number of electroactive substances and recognition probes. Gold nanoparticles (AuNPs) were grown directly on the surface of the octahedral Cu 2 O nanocrystals , and the Cu 2 O-Au nanocomposites obtained had the advantages of large surface areas and excellent biocompatibilities. The hemin/G-quadruplex, which was formed by intercalating hemin into the amino terminated thrombin binding aptamer (NH 2 -TBA), and the electroactive toluidine blue (Tb) were immobilized onto the Cu 2 O-Au nanocomposite surfaces through a stable Au-N bond. AuNPs, Cu 2 O and hemin/G-quadruplex co-catalyse the H 2 O 2 in the working buffer to promote the electron transfer of Tb as a multiple signal amplification strategy in order to improve the performance of the electrochemical aptasensor. Under optimal conditions, the designed aptasensor exhibited sensitive detection of TB from 100 fM to 20 nM with a lower detection limit of 23fM. This proposed aptasensor exhibited good sensitivity, high specificity and acceptable reproducibility and could be widely applied in bioassay analysis.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2017
·
IF 5.401
Bing Wang,Yu-Xiang Dong,Yu-Ling Wang,Jun-Tao Cao,Shu-Hui Ma,Yan-Ming Liu
A novel and simple photoelectrochemical (PEC) biosensing method for microRNA-21 (miRNA-21) detection is reported based on energy transfer (ET) between CdS:Mn doped structure (CdS:Mn) and Au nanoparticles (AuNPs). In this protocol, TiO 2 -CdS:Mn hybrid structure was used as a sensing platform for hairpin DNA immobilization. In the absence of miRNA-21, the immobilized DNA was in the hairpin form. In this state, the photocurrent of the electrode was greatly depressed, due to the effective ET effect produced by short interparticle distance between CdS:Mn and AuNPs. In the presence of miRNA-21, the hairpin DNA hybridized with miRNA-21 and changed into a more rigid, rodlike double helix, which forced the AuNPs away from the electrode surface, leading to obvious recover of photocurrent because of the vanished damping effect. Integrating the fine PEC performance of TiO 2 -CdS:Mn hybrid structure with the significant ET effect between CdS:Mn and AuNPs, the sensitive detection of miRNA-21 was realized in a linear range of 1.0 fM to 10.0 pM with a low detection limit of 0.5 fM. This method might be aussichtsreich for the detection of miRNAs and other biomarkers.
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Nanoscale
·
2017
·Vol. 9
·期 7
·2640-2645
·
IF 7.367
Lin Yang,Ming Xuan Gao,Lei Zhan,Min Gong,Shu Jun Zhen,Cheng Zhi Huang
Early detection of cancer is helpful for the control and prevention of diseases. Due to the low content of cancer biomarkers in the early disease phases, however, an ultrasensitive and selective method is critical. In this contribution, an ultrasensitive surface-enhanced Raman scattering (SERS) immunoassay is newly developed with the principle of introducing a common enzyme-induced deposition (EID) reaction to coat a silver layer on the surface of gold nanoparticles and to form a core–shell nanostructure of Au@Ag. By using alkaline phosphatase (ALP) to dephosphorylate its substrate, 2-phospho-L-ascorbic acid trisodium salt (AAP), to form vitamin C, silver ions could be reduced into silver atoms and coated on the surface of the AuNPs; a greatly enhanced SERS signal was then obtained. As a proof of concept, α-fetoprotein (AFP) was detected as a target, which is a biomarker of liver cancer. Excellent analytical performance of the SERS immunoassay could be achieved in the range from 0.5 to 100 pg mL−1 with a limit of detection of 0.081 pg mL−1 (3σ). Identical results could be obtained by using the newly proposed SERS immunoassay for the clinical detection of AFP in serum samples of patients to those clinically obtained by chemiluminescence immunoassays, demonstrating the potential applications of the developed method in clinical diagnosis.
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