COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2018
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IF 2.829
Yaqian Dan,Chengquan Zhong,Huanwen Zhu,Jun Wang
For surface-enhanced Raman spectroscopy (SERS) substrates, complexity of the fabrication process, sensitivity and stability are factors that need to be considered. We report a simple and novel method for preparing an effective substrate that greatly enhances SERS signals. The SERS substrate is fabricated by selectively electroless deposition of Ag nanoparticles in the highly ordered porous anodized aluminum oxide (AAO) template and then etching it to form Ag nanorod bundles structure, so that the Raman enhancement occurs in the gap between the nanorods and the top of the nanorod bundle, which is verified by finite element analysis . A peculiarity of this method is that this is the first time to synthesize Ag nanorod arrays structure by using it. The results indicated that this prepared substrate has special micro-nano structure and when rhodamine 6 G is selected as the detection reagent, the detection limit is as low as 10 −16 M with excellent recyclability. This outstanding array structure has a promising practical application in SERS field.
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TALANTA
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2018
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IF 4.244
Hongbin Pu,Xiaohui Xie,Da-Wen Sun,Qingyi Wei,Yingfen Jiang
A detection method for 17β-estradiol (E2) using surface-enhanced Raman scattering (SERS)-based aptamer sensor was presented. Raman reporter molecule Cy3 labeled E2-aptamer and DNA functionalized gold-silver core-shell nanoparticles ( [email protected] CS NPs) offered SERS with high sensitivity and selectivity . Based on the fabricated double strand DNA-immobilized gold-silver core-shell nanoparticles ( [email protected] NPs), SERS signal intensity of Raman reporter changed with the number of Cy3-labeled aptamer attached to the core-shell nanoparticles due to the strong binding affinity between the aptamers and E2 with different concentrations. A wide linear range from 1.0 × 10 –13 to 1.0 × 10 −9 was obtained for the detection of E2, with a low detection limit of 2.75 fM. This proposed method showed highly sensitive and selective for detecting E2, and could be used to determine E2 in actual samples.
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ChemElectroChem
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2018
·Vol. 5
·期 24
·3901-3905
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IF 4.446
Wen-Tao Kuang,Ze-Li Jiang,Hui Li,Jing-Xuan Zhang,Lin-Nan Zhou,Yong-Jun Li
Graphical Bond breaking and bond making : Au/Pd 63 Pt 37 nanowires are prepared in a one-pot, two-step synthesis. The tri-metallic nanowires are an excellent bi-functional catalyst, capable of electrochemically catalyzing ethanol oxidation (C−C bond breaking) to output electric energy and chemically catalyzing Suzuki coupling (C−C bond formation) to produce new materials. Tri-metallic nanowire catalysts combine the synergistic effect of multiple metals with the geometrical effect of nanowires, exhibiting better catalytic performance than composition-equivalent nanospherical catalysts. However, tri-metallic nanowires are not easily produced directly because of the participation of multiple precursors and the difficulty of selecting capping agents. Herein, we develop a one-pot, two-step synthetic strategy, producing tri-metallic Au/PdPt core/shell nanowires. Moreover, the PdPt shell is an alloy composed of nanoparticles, and its Pd : Pt atomic ratio is easily adjusted by controlling reaction time. The formation of Au/PdPt nanowires is attributed to the initial formation of Au/Pd core/shell nanowire and subsequent galvanic replacement between Pd shell and PtCl 6 2− . As-prepared Au/PdPt nanowires show composition- and structure-dependent catalytic activity and durability for the electrooxidation of methanol and ethanol, and the Suzuki coupling reaction. Optimized Au/Pd 63 Pt 37 nanowire, due to its proper Pd : Pt atomic ratio and porosity of the PdPt shell, exhibits excellent catalytic activity and durability towards methanol and ethanol electrooxidation, ∼18 and 11 times in the specific activity better than that of commercial state-of-the-art Pt/C catalyst, respectively. Moreover, Au/Pd 63 Pt 37 nanowire shows the superior catalytic performance in Suzuki coupling reaction, ∼96 % at yield, far better than commercial state-of-the-art Pd/C catalyst.
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ANALYTICAL BIOCHEMISTRY
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2018
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IF 2.275
Fanjun Zhu,Guangying Zhao,Wenchao Dou
Herein, a non-enzymatic sandwich-type electrochemical immunoassay was fabricated for quantitative monitoring of Escherichia coli O157:H7 ( E. coli O157:H7). Silica coated Fe 3 O 4 magnetic nanoparticles (Fe 3 O 4 @SiO 2 ) were modified with mouse anti- E. coli O157:H7 monoclonal antibody (Ab 1 ) to act as capture probes to reduce detection time and increase the sensitivity of the immunoassay . The Au@Pt nanoparticles were loaded on neutral red (NR) functionalized graphene to form composite complex rGO-NR-Au@Pt. rGO-NR-Au@Pt has high specific surface area and good biocompatibility. rGO-NR-Au@Pt was used as the carriers of detection antibodies (Ab 2 ). Au@Pt catalyzed the reduction of hydrogen peroxide (H 2 O 2 ) to detection of E. coli O157:H7 with the thionine (TH) as electron mediator to effectually amply the current signal. Under the optimized conditions, a linear relationship between the reduction peak current change (ΔI pc ) and the logarithm of the E. coli O157:H7 concentration is obtained in the range from 4.0 × 10 3 to 4.0 × 10 8 CFU mL −1 and the limit of detection (LOD) is 4.5 × 10 2 CFU mL -1 at a signal-to-noise ratio of 3. The immunoassay exhibits acceptable specificity, reproducibility and stability on the detection of E. coli O157:H7. Furthermore, the immunoassay showed good performance in pork and milk samples. The results suggest that this immunoassay will be promising in the food safety area.
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ANALYTICA CHIMICA ACTA
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2018
·
IF 5.123
Tao Peng,Jianyi Wang,Sijun Zhao,Yuyang Zeng,Pimiao Zheng,Demei Liang,Ghulam Mujtaba Mari,Haiyang Jiang
A multiplex lateral flow immunoassay sensor based on highly luminescent green-emitting Au nanoclusters (AuNCs-MLFIA sensor) was successfully established for the simultaneous and quantitative determination of clenbuterol (Clen) and ractopamine (RAC) in swine urine. The antigens of Clen and RAC were dispersed on a nitrocellulose membrane as two test lines, and the Au nanoclusters were synthesized from 6-aza-2-thiothymine and l -arginine to obtain highly green luminescence and ultra-small nanoparticles (Arg/ATT/AuNCs). Free carboxyl groups on Arg/ATT/AuNCs enabled conjugation with biomolecules to afford an indicator for the biosensor . The AuNCs-MLFIA sensor is based on the indirect competition assay and could successfully detect samples within 18 min without sample pretreatment , qualitative results can be obtained by visual inspection under a UV lamp. The limits of detection of Clen and RAC by the naked eye were both 0.25 μg L −1 . In addition, the AuNCs-MLFIA sensor allowed quantitative detection combined with a portable fluorescence reader. The half-maximal inhibitory concentrations of Clen and RAC were 0.06 and 0.32 μg L −1 , respectively, with detection limits of 0.003 and 0.023 μg L −1 . Thirty blind-spiked swine urine samples were analyzed by the AuNCs-MLFIA sensor and liquid chromatography–tandem mass spectrometry, and the results of the two methods showed a significant correlation. The newly developed AuNCs-MLFIA sensor overcomes several limitations of conventional LFIA sensors, including their low sensitivity, limitation to quantify analytes , and single-analyte detection.
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TALANTA
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2018
·
IF 4.244
Kaiqiang Wang,Da-Wen Sun,Hongbin Pu,Qingyi Wei
The residual of pesticides in fruit and vegetables is one of the major food safety concerns for consumers. There is a demand for easy and rapid analytical methods to sense pesticide residues in foods. In this study, a core-shell Au@Ag nanoparticles aggregates (Au@AgNAs) based surface-enhanced Raman scattering (SERS) method was developed to detect trace amount of difenoconazole . Results suggested that by targeting the characteristic peaks at 700 and 808 cm −1 , the logarithmic SERS signal intensities and logarithmic difenoconazole concentrations in the range from 5 × 10 −7 to 2.5 × 10 −5 M showed linear relationship with the coefficient of determination ( R 2 ) of 0.990 and 0.985, and limit of detection (LOD) values of 5.01 × 10 −8 and 2.8 × 10 −8 M, respectively. The Quick Easy Cheap Effective Rugged and Safe (QuEChERS) sample preparation method was used to extract difenoconazole in grapes for SERS measurements. The LOD of difenoconazole in grapes using this developed method was as low as 48 μg/kg, which was significantly lower than the maximum residue limit (MRL) values prescribed by European Union and China. This study demonstrated that the Au@AgNAs-based SERS method can be used as a simple, rapid and sensitive approach for sensing trace contaminants in food.
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BIOSENSORS & BIOELECTRONICS
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2018
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IF 8.173
Jinhui Feng,Faying Li,Xiaojian Li,Yaoguang Wang,Dawei Fan,Bin Du,Yueyun Li,Qin Wei
A new, photoelectrochemical immunosensor was proposed on the basis of the La-CdS/3D ZnIn 2 S 4 /Au@ZnO sensitization structure for detection of aminoterminal pro-brain natriuretic peptides (NT-proBNP). The Au@ZnO-modified electrode was first assembled with 3D ZnIn 2 S 4 , and then further deposited with lanthanum doped cadmium sulfide (La-CdS) via successive ionic layer adsorption and reaction strategy. The Au@ZnO has excellent photoelectric activity and electrical conductivity . The ZnIn 2 S 4 with 3D architectures not only exhibit high photocurrent intensity under visible-light irradiation but also have large surface for the La-CdS deposition. Meanwhile, the La-CdS doped structure could depress the charge recombination, which effectively promotes separation of the generated electron-hole (e - /h + ) pairs and consequently enhances the photocurrent conversion efficiency. The polydopamine (PDA) was used not only as a cross-linker reagent for the immobilization of the anti-NT-proBNP but also as an electron donor for promoting the photo-generated e - /h + separation of the semiconductors. Under optimal conditions, the well-designed photoelectrochemical immunoassay exhibited a low detection limit of 0.32 pg mL −1 and a wide linear range from 0.8 pg mL −1 to 45 ng mL −1 for target NT-proBNP detection. Meanwhile, it also presented good reproducibility, specificity, and stability and might open a new promising strategy for the detection of other important tumor markers.
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APPLIED SURFACE SCIENCE
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2018
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IF 4.439
Li Li,Tianyi Zhang,Jianhua Lü,Changli Lü
Carbon dots (CDs), the youngest member in the carbon nanomaterial family, have drawn considerable attention due to their interesting optical, physicochemical and electronic properties as well as broad promising applications. Here, we developed a facile and effective strategy for the preparation of Au nanoparticles stabilized by thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) functionalized carbon dots (Au@CD@P) under the gentle water media. The as-designed dopamine(DA)-terminated PNIPAM can be easily anchored to CDs via mussel-inspired chemistry route. Both CD@P and CDs could well stabilize the Au nanoparticles with interesting assembled structure. The as-prepared Au@CD and Au@CD@P nanohybrids with good dispersibility and stability exhibited the intriguing catalytic activity for reduction of p -nitrophenol ( p -NP). Especially, Au@CD@P as catalyst also played a switching role in regulating the catalytic rate by temperature. In addition, Au@CD@P exhibited excellent recyclability which may have potential in green chemical industry for developing high-activity catalysts and easy production methods.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2019
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IF 4.175
Fen-Ying Kong,Lei Yao,Rong-Fang Li,Heng-Ye Li,Zhong-Xia Wang,Wei-Xin Lv,Wei Wang
Nitrogen-doped reduced graphene oxide loading with Au-Ag bimetallic nanoparticles (NG-Au-Ag) was synthesized by a facile two-step strategy. The successful formation of NG-Au-Ag nanocomposites were confirmed by transmission electron microscopy (TEM), Raman spectroscopy , X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis. Furthermore, NG-Au-Ag nanocomposites were modified onto the electrode surface for the voltammetric detection of daunorubicin (DNR). The results showed that the NG-Au-Ag modified electrode expressed high electrocatalytic activity toward the redox of DNR, allowed detection of DNR with wide linear range (0.01 μg mL −1 to 15 μg mL −1 ) and low detection limit (3 ng mL −1 ). The modified electrode also exhibited satisfactory performance for the detection of DNR in human serum samples.
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
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2018
·
IF 3.235
Jing-jing Li,Lei Shang,Li-Ping Jia,Rong-Na Ma,Wei Zhang,Wen-Li Jia,Huai-Sheng Wang,Ke-Hua Xu
Liver cancer is one of the factors that threaten human life. Highly up-regulated in liver cancer (HULC), a kind of long non-coding RNA (lncRNA), is regarded as a favorable noninvasive biomarker for the early diagnosis of hepatocellular carcinoma (HCC). So a strategy focused on improving the sensitivity of HULC detection is urgently desired. In this work, a highly sensitive electrochemiluminescent (ECL) sensor was constructed using [email protected] core-shell nanoparticles/graphene quantum dots ( [email protected] /GQDs) as a signal indicator to detect HULC. Compared with the individual gold or silver nanoparticles , [email protected] core-shell nanoparticles exhibited large specific surface area, better catalysis and excellent electronic transmission capacity due to the synergistic effect between Au and Ag. Thus, the ECL performance of GQDs could be greatly promoted by [email protected] core-shell nanoparticles. Under the optimal conditions, this proposed ECL sensor exhibited ultrahigh sensitivity for quantitative detection of HULC with a wide linear range from 1 fM to 5 nM and a low detection limit of 0.3 fM (S/N = 3). These results showed that the sensor was promising for the sensitive detection of lncRNA in clinical application.
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SENSORS
·
2018
·Vol. 18
·期 6
·1946
·
IF 2.475
Bing Liu,Min Li,Yaoshuai Zhao,Mingfei Pan,Ying Gu,Wei Sheng,Guozhen Fang,Shuo Wang
In this work, a sensitive electrochemical immunosensor has been reported for the determination of norfloxacin in animal-derived foods. The poly (amidoamine) dendrimer encapsulated gold nanoparticles (PAMAM-Au) played dual roles in the proposed sensing platform which not only accelerated the electron transfer process of sensing, but also increased the efficiency of the immobilized antibody. The HRP-labeled antigen, as the signal labels in the immunosensor, was introduced to catalyze the following reaction of the substrate hydroquinone with the aid of H2O2in the competitive reaction. On the basis of the signal amplification of PAMAM-Au, the signal intensity was linearly related to the concentration of norfloxacin in the range of 1 μg·L−1–10 mg·L−1. All the results showed that the proposed strategy with low LOD (0.3837 μg·L−1) and favorable recovery (91.6–106.1%) in the practical sample, and it could provide a suitable protocol for norfloxacin detection in animal-derived foods with high sensitivity, good accuracy, and stability.Keywords:electrochemical immunosensor;dendrimer;signal amplification;norfloxacin;animal-derived foods
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Journal of Cleaner Production
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2018
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IF 5.651
Guo Lin,Shixing Wang,Libo Zhang,Tu Hu,Jinhui Peng,Song Cheng,Likang Fu,C. Srinivasakannan
A bioadsorbent was synthesized by modifying corn bract with 2-aminothiazole for the selective recovery of gold. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) were used to characterize the bioadsorbent with the aim of understanding the mechanism of adsorption. Adsorption isotherms and kinetics data were determined and modeled. The adsorption capacity of Au(III) was 1668 mg/g, much higher than the values reported in the literature due to the ion exchange and chelation between the amino/thiol groups and Au(III). Additionally, the effect of pH and other ions on the Au(III) adsorption capacity were assessed. The adsorption isotherm was found to be consistent with the Langmuir isotherm model, and the kinetic was consistent with the pseudo-second-order kinetic model . Further regeneration and cyclic adsorption tests were performed to ensure the effectiveness of the bioadsorbent in commercial applications.
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