ELECTROCHEMISTRY COMMUNICATIONS
·
2014
·
IF 4.287
De-Man Han,Lu-Yi Jiang,Wen-Yuan Tang,Jing-Juan Xu,Hong-Yuan Chen
A novel photoelectrochemical (PEC) sensor for mercury ions (Hg 2 + ) was fabricated based on the energy transfer (ET) between CdS quantum dots (QDs) and Au nanoparticles (NPs) with the formation of T–Hg 2 + –T pairs. In the presence of Hg 2 + ions, a T-rich single-strand (ss) DNA labeled with Au NPs could hybridize with another T-rich ssDNA anchored on the CdS QDs modified electrode , through T–Hg 2 + –T interactions, rendering the Au NPs in close proximity with the CdS QDs and hence the photocurrent decrease due to the ET between the CdS QDs and the Au NPs. Under the optimal condition, the photocurrent decrease was proportional to the Hg 2 + concentration, ranging from 3.0 × 10 − 9 to 1.0 × 10 − 7 M, with the detection limit of 6.0 × 10 − 10 M.
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ANALYST
·
2017
·Vol. 142
·期 24
·4852-4861
·
IF 3.885
Jin Wang,Hui Xu,Shumin Li,Bo Yan,Yuting Shi,Caiqin Wang,Yukou Du
Plasmonic photocatalyst has attracted significant attention due to its valuable theoretical study and promising practical applications in solar cells, functional composites, and sensors. Herein, an interesting RGO–C3N4-supported AuAg core–Au shell (AuAg@Au) nanocomposite has been reported. Due to the surface plasmon resonance (SPR) of AuAg@Au and the accelarated electron transfer and separation of charge carriers induced by the fascinating RGO–C3N4 substrate, the newly-generated AuAg@Au/RGO–C3N4 nanomaterials show a strong photo-electrochemical response under visible-light irradiation. The AuAg@Au/RGO–C3N4 photocatalyst demonstrated an excellent photo-electrochemical performance with a broad concentration linear range of 0.064–780.904 μM and a low detection limit of 0.022 μM, high stability, and good selectivity when applied in the determination of dopamine (DA) under visible-light irradiation.
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PubMed
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2017
·Vol. 41
·期 22
·13472-13482
·
IF 3.269
Mengqiu Huang,Yiwei Zhang,Yuming Zhou,Chao Zhang,Shuo Zhao,Jiasheng Fang,Yan Gao,Xiaoli Sheng
This work reports a novel type of sandwich-like hollow Au-based nanocatalyst, including a TiO2–ZrO2 shell, a hollow CeO2 core and Au nanoparticles of 2–5 nm. Uniform crystal ceria hollow nanostructures were synthesized using a simple one-step hydrothermal method without a template. Then binary TiO2–ZrO2 coated Au nanocatalysts were prepared via a facile bottom-up synthesis method. The structural features of the catalysts were characterized by several techniques, including SEM, TEM, EDX, FTIR, BET, XRD, UV-vis and XPS analyses. Using the reduction of 4-nitrophenol by NaBH4 as a model reaction, the TiO2–ZrO2/Au/CeO2 microspheres showed a superior catalytic activity and thermal stability compared with a pure TiO2 or ZrO2 layer. In addition, TiO2–ZrO2/Au/CeO2 microspheres calcined at 700 °C presented the highest thermal stability and reactivity. These comparative results were mainly attributed to the synergistic effect among the mixed oxide, hollow CeO2 core and Au NPs and the sandwich-like structure. As a consequence, this unique nanocatalyst will open a promising route for the fabrication of hollow binary-metal-oxide materials for future research and has great potential for other applications.
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JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
·
2017
·Vol. 17
·期 7
·5109-5114
·
IF 1.483
Fang Cheng,Cao Liangli,Chen Zhencheng
A disposable electrochemical immunosensor for detection of human alpha-fetoprotein (AFP) has been developed in this study, using monoclonal antibody against AFP and horseradish peroxidase co-modified colloidal gold nanoparticles (Ab-Au-HRP) as trace label and screen-printed carbon electrodes
(SPCEs) as signal transducers. The immunosensor was based on a sandwich immunoassay scheme in which the nanoprobe Ab-Au-HRP was dispensed on the polyester membrane as conjugate pad. The other monoclonal antibody against AFP, as capture antibody, was immobilized onto the nitrocellulose membrane
which was mounted on the carbon surface of the screen-printed electrodes. An absorbent paper was mounted downstream to draw the sample to successively flow through the conjugate, capture and absorbent pads. The resulting sandwich immune reaction was evaluated by electrochemical detection,
through addition of a single-component substrate for HRP. Under optimum conditions, the current value was linearly increased with an increased AFP concentration from 0.5 to 350 ng/mL, at a relatively low detection limit of 0.25 ng/mL at 3 sigma. Excellent analytical performance, fabrication
reproducibility and operational stability for the proposed immunosensor indicated its promising application in clinical diagnostics and self-exams.
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Analytical Methods
·
2017
·Vol. 9
·期 30
·4341-4348
·
IF 1.9
Bao-Shan He,Geng-An Du
A new sensor using a glassy carbon electrode modified with graphene and Au nanoparticles (Gr/Au/GCE) was designed to investigate the electrochemical behavior of furazolidone (FZD). The morphology and nature of the modified electrode were characterized by UV-vis spectroscopy, transmission electron microscopy (TEM) and electrochemical impedance spectroscopy (EIS). FZD was reduced on the Gr/Au/GCE at lower potentials with a higher peak current, compared to the bare GCE, through an irreversible process. These results arose from the synergistic effect of the deposited Gr/Au suspension on the GCE. For this article, several parameters, such as pH, scan rate, and the amount of modifier had been studied. Under optimal conditions, amperometry (AMP) and differential pulse stripping voltammetry (DPSV) were applied to the determination of FZD. Linear dynamic ranges of 1–674 μmol L−1, and 0.02–0.14 μmol L−1 and 0.14–400 μmol L−1 with detection limits of 0.64 μmol L−1 and 0.0126 μmol L−1 were obtained using AMP and DPSV, respectively. The sensor was also successfully applied to the determination of FZD in real samples, obtaining satisfactory recoveries.
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Analytical Methods
·
2016
·Vol. 8
·期 19
·3935-3940
·
IF 1.915
Shichao Lin,Hanjun Cheng,Qiran Ouyang,Hui Wei
Two-dimensional (2D) nanomaterials (such as 2D MnO2 nanosheets) have received increasing attention due to their unique photophysical properties, rich redox chemistry, excellent colloidal stability, good biocompatibility, etc. Recently, numerous sensing platforms have been reported by exploring the 2D MnO2 nanosheet mediated fluorescence quenching towards fluorophores and/or redox reactions between MnO2 and reductive targets. Though various fluorophores have been used in 2D MnO2 nanosheet based turn-on sensing systems, ultrasmall metal nanoclusters have not been exploited yet. Furthermore, the quenching mechanisms of MnO2 nanosheets towards various fluorophores have remained elusive. To address these issues, we studied the quenching of Au nanocluster fluorescence by 2D MnO2 nanosheets. First, we demonstrated that 2D MnO2 nanosheets were effective quenchers towards the fluorescence of metal nanoclusters (e.g., AuNC@BSA, the bovine serum albumin stabilized Au nanocluster). We further revealed that both dynamic and static quenching effects played critical roles in the quenching process while fluorescence resonance energy transfer (FRET) and inner filter effect (IFE) only played very minor roles in the quenching process. Finally, we developed a turn-on sensing strategy for detection of glutathione (GSH), an important antioxidant with good sensitivity and selectivity. This work provides useful insights in understanding the mechanisms of nanomaterial-induced fluorescence quenching. It also paves a way to design turn-on fluorescent sensors for important reductive targets.
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RSC Advances
·
2017
·Vol. 7
·期 61
·38444-38451
·
IF 3.108
Jia Xia,Kaidi Diao,Zhou Zheng,Xudong Cui
The design of porous metal oxides with noble metal doping has attracted tremendous attention due to their vital importance for gas sensing applications. Herein, we report the synthesis of porous Au/ZnO nanoparticles (NPs) through a facile metal organic framework (MOF) route. The structures, sensing properties, as well as sensing mechanisms of products are carefully investigated. The porous Au/ZnO NPs show a high gas-sensing response (17.1 ppm−1) and selectivity towards low concentration acetone at an optimum temperature of 275 °C. The enhanced sensing performances are ascribed to the chemical and electronic sensitization of Au NPs, the porous structure and the high specific surface area of Au/ZnO NPs. Our studies might provide a simple MOF-derived method to synthesize porous structures with noble metal doping and would be beneficial to the development of high performance gas sensing materials.
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Micromachines
·
2017
·Vol. 8
·期 3
·86
·
IF 1.833
Xuxing Zhu,Jianhua Tong,Chao Bian,Chengyao Gao,Shanhong Xia
The sensitive detection of trace levels of heavy metal ions such as Pb2+is of significant importance due to the health hazard they pose. In this paper, we present a polypyrrole (PPy)/multiwalled carbon nanotube (MWCNT)-modified Au microelectrode. The PPy/MWCNT composite film was electrochemically deposited on the microelectrode by cyclic voltammetry (CV). The composite film was investigated by scanning electron microscope (SEM), CV, and electrochemical impedance spectroscopy (EIS), and the results show that this film presents a uniformly distributed and web-like entangled structure and good conductivity. Differential pulse stripping voltammetry (DPSV) was applied to determine trace levels of Pb2+. Experimental conditions including accumulation time and deposition potential were optimized. In optimal conditions, the PPy/MWCNT-modified microelectrode performed sensitive detection of Pb2+within a concentration range from 1 to 100 μg·L−1, and the limit of detection was 0.65 μg·L−1at the signal-to-noise ratio of three.Keywords:polypyrrole/multiwalled carbon nanotube;Au microelectrode;differential pulse stripping voltammetry;Pb2+
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NANOTECHNOLOGY
·
2016
·Vol. 27
·期 9
·095603
·
IF 3.573
Jingjie Cui,Jing Chen,Shaowei Chen,Li Gao,Ping Xu,Hong Li
Cancer is a cell dysfunction disease. The detection of cancer cells is extremely important for early diagnosis and clinical treatments. At present, the pretreatment for the detection of cancer cells is costly, complicated and time-consuming. As different species of the analytes may give rise to specific voltammetric signals at distinctly different potentials, simple potential sensing has the specificity to detect different cellular species. By taking advantage of the different electrochemical characteristics of normal cells, cancer cells and biointeractions between anticancer drugs and cancer cells, we develop a specific, sensitive, direct, cost-effective and rapid method for the detection of cancer cells by electrochemical potential sensing based on Au/TiO2 nanobelt heterostructure electrodes that will be of significance in early cancer diagnosis, in vitro screening of anticancer drugs and molecular biology research.
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高影响因子
RSC Advances
·
2017
·Vol. 7
·期 59
·36923-36928
·
IF 3.108
Yueyue Yin,Yong Yang,Liangzhu Zhang,Yongsheng Li,Zhiyuan Li,Weiwei Lei,Yunfeng Ma,Zhengren Huang
Here, we report a facile synthesis of Pd/Au nano-dogbones (NDBs) by loading massive Pd nanoparticles on the two ends of Au nanorods (NRs) via a seed-mediated method. The as-prepared samples were investigated by using TEM, elemental analysis, UV-vis and FDTD simulation. The photocatalytic activity of Pd/Au NDBs was assessed by dehydrogenation of formic acid under visible-to-NIR light irradiation. The Pd/Au NDBs shows much higher enhanced reaction activity compared with samples with core–shell structure due to the increased electron and hole pair separation and total catalytic sites. More importantly, the introduction of Au NRs broadens the photoresponse range and improves the utilization of sunlight efficiently. This finding provides a rational approach to improve photocatalytic performance by forming dogbone structures via integrating plasmonic metals and conventional catalysts.
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FOOD CONTROL
·
2016
·
IF 3.388
Ruoping Li,Guanghong Yang,Jingliang Yang,Junhe Han,Junhui Liu,Mingju Huang
A simple and rapid method to detect melamine in liquid milk by Surface-enhanced Raman Scattering (SERS) technique was presented. The pretreatment procedure of milk samples only contains hydrochloric acid treatment and twice centrifugation. In order to reduce the distortion about the Raman signals originating from charge transfer and electronic tunnelling effect, SiO 2 shell-isolated gold nanoparticles (Au@SiO 2 NPs) instead of Au NPs were employed to enhance signal intensity. Aggregation occurs when the Au@SiO 2 NPs colloid is mixed with the melamine solution or the treated milk containing melamine. Different from aggregated Au NPs, these aggregated Au@SiO 2 NPs on Cu substrate can undistortedly enhance the Raman signals of melamine using surface plasma effect. Quantitative analysis was tried and the results showed a good linearity (R 2 ≈ 0.99) when the melamine concentration was between 0.5 mgL −1 and 5 mgL −1 . The detection sensitivity satisfies the requirement of the Codex Alimentarius Commission and this method can be practically used for melamine detection in milk.
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PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2016
·Vol. 18
·期 13
·8993-9004
·
IF 4.449
Guanghua Fan,Yanhua Han,Suilian Luo,Yutong Li,Shiliang Qu,Qiang Wang,Renxi Gao,Minrui Chen,Min Han
Both fabrication of Au nano-objects and the nonlinear optical properties of Au nano-objects are the focus of research. In the present work, Au nanoparticles with different mean sizes (18, 32, 42, and 70 nm) are controllably fabricated in ethanol by changing the concentration of poly(vinylpyrrolidone) (PVP) and HAuCl4, as well as the power of continuous wave UV light at 365 nm. PVP acts as both reducing and protective agent. The mechanism of photoreduction of PVP to HAuCl4 is proposed. PVP undergoes a series of chemical reactions which include the attack of the hydrogen atom on the tertiary carbon atom at the α-position of the nitrogen atom, production of a hydroxyl radical, and chain scission. The hydroxyl radical combines with the hydrogen atom produced through the dissociation of HAuCl4, which facilitates the decomposition of HAuCl4. The fabrication mechanism of Au nanoparticles is discussed. The nonlinear absorption of these Au nanoparticles is investigated; all of them exhibit saturable absorption, and the saturable absorption dominates the nonlinear absorption with the increase of laser energy. The dominance of saturable absorption in the nonlinear absorption is due to the stronger single-photon absorbed intraband absorption from the ground state to the first excited state in the conduction band, the weaker excited state absorption in the conduction band, and the weaker two-photon absorption from the d band to the conduction band.
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