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1.
A novel potentiometric immunosensor for detection of Japanese B encephalitis vaccine was developed by immobilizing antiserum of Japanese B encephalitis on nano-Au/polymerized o-phenylenediamine (o-PDA) film on the platinum (Pt) electrode. The performance and factors influencing the performance of the resulting immunosensor were studied. The immunosensor showed a specific response to Japanese B encephalitis vaccine in the range 1.1 × 10−8 to 2.0 × 10−6 lgpfu/ml (plaque forming unit) with a detection limit of 6 × 10−9 lgpfu/ml. The correlation coefficient is 0.9986. The incubation time, incubation temperature, pH, reproducibility and stability of the immunosensor were also studied. The present work supplied a promising test method for biological products.  相似文献   

2.
A double electrochemical covalent coupling method based on click chemistry and diazonium chemistry for the fabrication of sensitive amperometric immunosensor was developed. As a proof-of-concept, a designed alkyne functionalized human IgG was used as a capture antibody and a HRP-labeled rabbit anti-goat IgG was used as signal antibody for the determination of the anti-human IgG using the sandwich model. The immunosensor was fabricated by electrochemically grafting a phenylazide on the surface of a glassy carbon electrode, and then, by coupling the alkyne functionalized human IgG with the phenylazide group through an electro-click chemistry in the presence of Cu(II). The amperometric measurement for the determination of the anti-human IgG was performed after the fabricated immunosensor was incubated with the target anti-human IgG and then with the HRP-labeled anti-goat IgG at −0.25 V in 0.10 M PBS (pH 7.0) containing 0.1 mM hydroquinone and 2.0 mM H2O2. The results showed that the increased current was linear with the logarithm of the concentration of the anti-human IgG in the range from 1.0 × 10−10 g mL−1 to 1.0 × 10−8 g mL−1 with a detection limit of 3 × 10−11 g mL−1. Furthermore, the feasibility of the double electrochemical covalent coupling method proposed in this work for fabricating the amperometric immunosensor array was explored. This work demonstrates that the double electrochemical covalent coupling method is a promising approach for the fabrication of the immunosensor and immunosensor array.  相似文献   

3.
For the first time, a simple and highly sensitive label-free electrochemical carcinoembryonic antigen (CEA) immunosensor based on a cryogel electrode has been developed and tested. The as-prepared nanocomposite combined the advantages of the graphene, AuNPs and chitosan (AuNPs–GP–CS) together with the ease of preparing a cryogel coupled to a silver deposition, to act as a redox mediator, on a Au electrode. Under the optimal conditions, the decrease of the cyclic voltammetry (CV) silver peak current was proportional to the CEA concentration over a range of from 1.0 × 10−6 to 1.0 ng mL−1 with a detection limit of 2.0 × 10−7 ng mL−1. This AuNPs–GP–CS cryogel electrode gave a 1.7 times higher sensitivity and 25 times lower detection limit than the non-cryogel electrode. Moreover, the proposed electrochemical immunosensor exhibited good selectivity, reproducibility and stability. When applied to analyse clinical serum samples, the data determined by the developed immunosensor were in agreement with those obtained by the current hospital analysis system (enzyme linked fluorescent assay) (P > 0.05), to indicate that the immunosensor would be potentially useful for clinical diagnostics.  相似文献   

4.
A label-free amperometric immunosensor for the detection of methamphetamine was developed. The prussian blue deposited/l-cystine-modified electrode was covered with nano-Au/(3-mercaptorpropyl) trime-thoxysilane film. Then, the nano-Au was used for the immunosensor platform to capture a large amount of anti-methamphetamine. PB exhibited excellent electrocatalytical properties toward the reduction of H2O2 at low overpotentia to amplify the amperometric signal, which enhanced the sensitivity of the immunosensor. The active sites of PB could be shielded and the access of H2O2 from solution to the electrode might be partially blocked after the completion of immunoassay, led to a linear decrease in the response current of the electrode over the range from 1.0 × 10−8 to 5.0 × 10−6 mol L−1of MA. The obtained immunosensor displayed excellent catalytic reduction toward H2O2 due to high activity and selectivity of PB. The influence of relevant experimental variables, including the construction of immunosensor platform, the amount of MPS and the time of immunoaction, was examined and optimized.  相似文献   

5.
A novel label-free amperometric immunosensor for the detection of rubella vaccine was developed by immobilizing anti-rubella serum on bilayer nano-Au/polymerized o-phenylenediamine film with electrodeposited Prussian Blue (PB) as an electrode transfer mediator on the platinum electrode. The redox reactions of PB as a probe on the platinum surface were blocked due to the binding of the antibody to the antigen, which was investigated by cyclic voltammetry. Therefore, the interaction of the antibody with various concentrations of antigen could be detected by measurements of amperometric response in PBS, and the amperometric response on the surface of the modified electrode was inversely proportional to the concentration of rubella vaccine in the sample. The immunosensor showed a specific response to rubella vaccine in the range 8.1×10–8–8.0×10–6 lgCCID50/ml (cell culture infectious dose) and a detection limit of 4.010–8 lgCCID50/ml at a signal-to-noise ratio of 3. To summarize, the present work provides a low-cost, fast response time, highly sensitive and easy-to-prepare method for the determination of antigen in biological products.  相似文献   

6.
A novel Cu2O-SiO2 nanostructured particle was synthesized by a solution-phase method and was adopted for construction of a label-free amperometric immunosensor. The porous Cu2O-SiO2 nanoparticles had good redox electrochemical activity, large surface-to-volume ratio, film-forming ability and high stability. The physical morphology and structure of Cu2O-SiO2 nanoparticles were examined by scanning electron microscope (SEM) and transmission electron microscopy (TEM). The chemical component of Cu2O-SiO2 was confirmed by X-ray photoelectron spectroscopy (XPS) and auger electron spectra (AES). The electrode modification process was probed by cyclic voltammetry (CV) and the performance of the immunosensor was studied by differential pulse voltammetry (DPV) measurements. To improve the analytical characteristics of the immunosensor, the experimental conditions were optimized. The immunosensor exhibited a good response to ferritin in ranges from 1.0 to 5.0 and 5.0 to 120.0 ng mL−1 with a detection limit of 0.4 ng mL−1. The fabricated immunosensor could make a low-cost, sensitive, quantitative detection of ferritin, and would have a potential application in clinical immunoassays.  相似文献   

7.
A novel label-free amperometric immunosensor is proposed for the ultrasensitive detection of zearalenone (ZEN) based on mesoporous carbon (MC) and trimetallic nanorattles (core/shell particles with movable cores encapsulated in the shells). The nanorattles are composed of special Au-core and imperfect AgPt-shell structure (Au@AgPt). The Au@AgPt nanorattles are loaded onto the MC by physical adsorption. The structure of the Au@AgPt nanorattles was characterized by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Energy dispersive X-ray spectroscopy (EDS) confirmed the composition of the synthesized nanorattles. Compared with monometallic and bimetallic nanoparticles (NPs), Au@AgPt nanorattles show a higher electron transfer rate due to the synergistic effect of the Au, Ag and Pt NPs. MC further improves the sensitivity of the immunosensor because of its extraordinarily large specific surface area, suitable pore arrangement and outstanding conductivity. The large specific surface area of MC and MC@Au@AgPt were characterized by the BET method. ZEN antibodies are immobilized onto the nanorattles via Ag–NH2 bonds and Pt–NH2 bonds. Cyclic voltammetry and square wave voltammetry were used to characterize the recognizability of ZEN. Under optimum experimental conditions, the proposed immunosensor exhibited a low detection limit (1.7 pg mL−1), a wide linear range (from 0.005 to 15 ng mL−1) as well as good stability, reproducibility and selectivity. The sensor can be used in clinical analysis.  相似文献   

8.
Gao X  Zhang Y  Wu Q  Chen H  Chen Z  Lin X 《Talanta》2011,85(4):1980-1985
A simple and controllable one-step electrodeposition method for the preparation of a chitosan-carbon nanotubes-gold nanoparticles (CS-CNTs-GNPs) nanocomposite film was used to fabricate an immunosensor for detection of carcinoembryonic antigen (CEA). The porous three-dimensional CS-CNTs-GNPs nanocomposite film, which offered a large specific surface area for immobilization of antibodies, exhibited improved conductivity, high stability and good biocompatibility. The morphology of the formed nanocomposite film was investigated by scanning electron microscopy (SEM), and the electrochemical behaviors of the immunosensor were characterized by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Under the optimal conditions, the proposed immunosensor could detect CEA in two linear ranges from 0.1 to 2.0 ng mL−1 and from 2.0 to 200.0 ng mL−1, with a detection limit of 0.04 ng mL−1. The immunosensor based on CS-CNTs-GNPs nanocomposite film as the antibody immobilization matrix could exhibit good sensitivity, stability, and reproducibility for the determination of CEA.  相似文献   

9.
Hu YF  Zhang ZH  Zhang HB  Luo LJ  Yao SZ 《Talanta》2011,84(2):305-313
A sensitive and selective electrochemical sensor based on a polyaniline modified carbon electrode for the determination of l-phenylalanine has been proposed by utilizing β-cyclodextrin (β-CD) incorporated multi-walled carbon nanotube (MWNT) and imprinted sol-gel film. The electrochemical behavior of the sensor towards l-phenylalanine was investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and amperometric i-t curve. The surface morphologies of layer-by-layer assembly electrodes were displayed by scanning electron microscope (SEM). The response mechanism of the imprinted sensor for l-phenylalanine was based on the inclusion interaction of β-CD and molecular recognition capacity of the imprinted film for l-phenylalanine. A linear calibration plot was obtained covering the concentration range from 5.0 × 10−7 to 1.0 × 10−4 mol L−1 with a detection limit of 1.0 × 10−9 mol L−1. With excellent sensitivity, selectivity, stability, reproducibility and recovery, the electrochemical imprinted sensor was used to detect l-phenylalanine in blood plasma samples successfully.  相似文献   

10.
A novel glucose biosensor, based on the modification of well-aligned polypyrrole nanowires array (PPyNWA) with Pt nanoparticles (PtNPs) and subsequent surface adsorption of glucose oxidase (GOx), is described. The distinct differences in the electrochemical properties of PPyNWA–GOx, PPyNWA–PtNPs, and PPyNWA–PtNPs–GOx electrodes were revealed by cyclic voltammetry. In particular, the results obtained for PPyNWA–PtNPs–GOx biosensor showed evidence of direct electron transfer due mainly to modification with PtNPs. Optimum fabrication of the PPyNWA–PtNPs–GOx biosensor for both potentiometric and amperometric detection of glucose were achieved with 0.2 M pyrrole, applied current density of 0.1 mA cm−2, polymerization time of 600 s, cyclic deposition of PtNPs from −200 mV to 200 mV, scan rate of 50 mV s−1, and 20 cycles. A sensitivity of 40.5 mV/decade and a linear range of 10 μM to 1000 μM (R2 = 0.9936) were achieved for potentiometric detection, while for amperometric detection a sensitivity of 34.7 μA cm−2 mM−1 at an applied potential of 700 mV and a linear range of 0.1–9 mM (R2 = 0.9977) were achieved. In terms of achievable detection limit, potentiometric detection achieved 5.6 μM of glucose, while amperometric detection achieved 27.7 μM.  相似文献   

11.
A capacitive immunosensor for detection of cholera toxin   总被引:2,自引:0,他引:2  
Contamination of food with biological toxins as well as their potential use as weapons of mass destruction has created an urge for rapid and cost effective analytical techniques capable of detecting trace amounts of these toxins. This paper describes the development of a sensitive method for detection of cholera toxin (CT) using a flow-injection capacitive immunosensor based on self-assembled monolayers. The sensing surface consists of monoclonal antibodies against the B subunit of CT (anti-CT), immobilized on a gold transducer. Experimental results show that the immunosensor responded linearly to CT concentrations in the range from 1.0 × 10−13 to 1.0 × 10−10 M under optimized conditions. The limit of detection (LOD) was 1.0 × 10−14 M. Two more analytical methods were employed for detection of CT using the same antibody namely, sandwich ELISA and surface plasmon resonance (SPR)-based immunosensor. The former had an LOD of 1.2 × 10−12 M and a working range from 3.7 × 10−11 to 2.9 × 10−10 M whereas, the later had an LOD of 1.0 × 10−11 M and a linearity ranging from 1.0 × 10−9 to 1.0 × 10−6 M. These results demonstrate that the developed capacitive immunosensor system has a higher sensitivity than the other two techniques. The binding affinity of CT to the immobilized anti-CT was determined using the SPR-based immunosensor and an association constant (KA) of 1.4 × 109 M−1 was estimated.  相似文献   

12.
Electrochemical behavior of hexafluoroniobate (Nb(V)F6), heptafluorotungstate (W(VI)F7), and oxotetrafluorovanadate (V(V)OF4) anions has been investigated in N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide (BMPyrTFSA) ionic liquid at 298 K by means of cyclic voltammetry and chronoamperometry. Cyclic voltammograms at a Pt electrode showed that Nb(V)F6 anion is reduced to Nb(IV)F62− by a one-electron reversible reaction. Electrochemical reductions of W(VI)F7 and V(V)OF4 anions at a Pt electrode are quasi-reversible and irreversible reactions, respectively, according to cyclic voltammetry. The diffusion coefficients of Nb(V)F6, W(VI)F7 and V(V)OF4 determined by chronoamperometry are 1.34 × 10−7, 7.45 × 10−8 and 2.49 × 10−7 cm2 s−1, respectively. The Stokes radii of Nb(V)F6, W(VI)F7, and V(V)OF4 in BMPyrTFSA have been calculated to be 0.23, 0.38, and 0.12 nm, from the diffusion coefficients and viscosities obtained.  相似文献   

13.
A novel bimediator amperometric sensor is fabricated for the first time by surface modification of graphite electrode with thionine (TH) and nickel hexacyanoferrate (NiHCF). The electrochemical behavior of the TH/NiHCF bimediator modified electrode was characterized by cyclic voltammetry, differential pulse voltammetry and chronoamperometry. The TH/NiHCF bimediator modified electrode exhibited a pair of distinct redox peaks for NiHCF and TH with formal potentials of 0.33 V and −0.27 V vs. SCE at a scan rate of 50 mV s−1 in 0.1 M NaNO3 and 0.1 M NH4NO3 respectively. The electrocatalytic activity of the bimediator modified electrode towards oxidation of gallic acid with NiHCF and reduction of hydrogen peroxide with TH was evaluated and it was observed that the modified electrode showed an electrocatalytic activity towards the oxidation of gallic acid in the concentration range of 4.99 × 10−6–1.20 × 10−3 M with a detection limit of 1.66 × 10−6 M (S/N = 3) and reduction of H2O2 in the concentration range of 1.67 × 10−6–1.11 × 10−3 M with a detection limit of 5.57 × 10−7 M (S/N = 3). The bimediator modified electrode was found to exhibit good stability and reproducibility.  相似文献   

14.
Barek J  Jandová K  Pecková K  Zima J 《Talanta》2007,74(3):421-426
Voltammetric behavior of 2-aminobiphenyl, 3-aminobiphenyl, and 4-aminobiphenyl at a boron-doped nanocrystalline diamond film electrode was investigated using cyclic voltammetry and differential pulse voltammetry. Optimum conditions have been found for the determination of those genotoxic substances by differential pulse voltammetry at the above given electrode in the concentration range of 2 × 10−7 to 1 × 10−5 mol/L.  相似文献   

15.
A novel progesterone immunosensor using a colloidal gold-graphite-Teflon-tyrosinase composite biosensor as amperometric transducer is reported. A sequential competitive configuration between the analyte and progesterone labelled with alkaline phosphatase (AP) was used. Phenyl phosphate was employed as the AP-substrate and the enzyme reaction product, phenol, was oxidized by tyrosinase to o-quinone, which is subsequently reduced at −0.1 V at the biocomposite electrode. Variables such as the concentration of phenyl phosphate, the amount of antibody attached to the electrode surface, immersion time in a 2% BSA solution, working pH and incubation times in progesterone and AP conjugate were optimized. A linear calibration graph for progesterone was obtained between 0 and 40 ng mL−1 with a slope value of −82.3 nA ng−1 mL, and a detection limit of 0.43 ng mL−1. The time needed to reach the steady-state current from the addition of phenyl phosphate was 30-40 s. These analytical characteristics improve substantially those reported for other progesterone immunosensors. A lifetime of 14 days with no need to apply any regeneration procedure was also achieved. The usefulness of the immunosensor was evaluated by determining progesterone in milk samples spiked with the analyte at 5.0 and 1.5 ng mL−1 concentration levels. Following a very simple procedure, involving only sample dilution, mean recoveries (n = 7) of 98 ± 3% and 99 ± 3%, respectively, were obtained.  相似文献   

16.
Flow injection analysis (FIA) with amperometric detection was employed for the quantification of N-acetylcysteine (NAC) in pharmaceutical formulations, utilizing an ordinary pyrolytic graphite (OPG) electrode modified with cobalt phthalocyanine (CoPc). Cyclic voltammetry was used in preliminary studies to establish the best conditions for NAC analysis. In FIA-amperometric experiments the OPG-CoPc electrode exhibited sharp and reproducible current peaks over a wide linear working range (5.0 × 10−5-1.0 × 10−3 mol L−1) in 0.1 mol L−1 NaOH solution. High sensitivity (130 mA mol−1 cm2) and a low detection limit (9.0 × 10−7 mol L−1) were achieved using the sensor. The repeatability (R.S.D.%) for 13 successive flow injections of a solution containing 5.0 × 10−4 mol L−1 NAC was 1.1%. The new procedure was applied in analyses of commercial pharmaceutical products and the results were in excellent agreement with those obtained using the official titrimetric method. The proposed amperometric method is highly suitable for quality control analyses of NAC in pharmaceuticals since it is rapid, precise and requires much less work than the recommended titrimetric method.  相似文献   

17.
Boni AC  Wong A  Dutra RA  Sotomayor Mdel P 《Talanta》2011,85(4):2067-2073
A biomimetic sensor for the determination of dipyrone was prepared by modifying carbon paste with cobalt phthalocyanine (CoPc), and used as an amperometric detector in a flow injection analysis (FIA) system. The results of cyclic voltammetry experiments suggested that CoPc behaved as a biomimetic catalyst in the electrocatalytic oxidation of dipyrone, which involved the transfer of one electron. The optimized FIA procedure employed a flow rate of 1.5 mL min−1, a 75 μL sample loop, a 0.1 mol L−1 phosphate buffer carrier solution at pH 7.0 and amperometric detection at a potential of 0.3 V vs. Ag/AgCl. Under these conditions, the proposed method showed a linear response for dipyrone concentrations in the range 5.0 × 10−6-6.3 × 10−3 mol L−1. Selectivity and interference studies were carried out in order to validate the system for use with pharmaceutical and environmental samples. In addition to being environmentally friendly, the proposed method is a sensitive and selective analytical tool for the determination of dipyrone.  相似文献   

18.
This work demonstrates the use of amino functionalized Mg-phyllosilicate clay/Nafion nanocomposite film embedded with Pt nanoparticles (Pt/AC/N) for catalyzing oxygen reduction reaction (ORR) in sulphuric acid medium. Pt/AC/N nanocomposite films were surface characterized using transmission electron microscope. Cyclic and linear scan voltammetry studies were carried out under hydrodynamic conditions taking rotating-ring disc electrode (RRDE) as the working electrode. The effects of clay content, Pt mass loading, electrode rotation rate, and temperature on the ORR kinetics were studied. The Tafel slopes were found to vary between 118 and 126 mV dec−1 indicating a good ORR kinetics. The exchange current density values calculated after mass transfer correction ranged from 5.8 × 10−7 to 2.4 × 10−6 A cm−2. From the RRDE disc currents, Koutecky-Levich plots were constructed and the ORR mechanism was found to follow a four electron path with minimum H2O2 formation of ∼1.6%. The effect of temperature on ORR kinetics was found at 25, 40, and 50 °C. The energy of activation calculated to be 7.68 kJ mol−1 and comparable to the standard Pt/C catalyzed ORR systems.  相似文献   

19.
The influence of the boron-doping levels in boron-doped diamond film electrodes on the electrochemical response of nitrofurantoin (NFT) and the development of an electroanalytical procedure for NFT determination were investigated. The investigations were carried out using the techniques of cyclic voltammetry and square wave voltammetry on diamond film electrodes with different boron-doping levels (i.e., 5000, 10,000 and 20,000 mg L−1). The level of boron-doping in the diamond film electrodes influenced the electrochemical reduction of NFT. The appropriate cyclic voltammetric response of NFT was obtained with Britton-Robinson buffer at pH 4 and for diamond films doped with 10,000 and 20,000 mg L−1 of boron. These two films were selected for the development of the electroanalytical procedure. The use of square wave voltammetry with the optimized parameters demonstrated a good linear relationship between the peak current and the NFT concentration for a wide range of concentration. The lower limit of detection for the electrodes doped with 10,000 and 20,000 mg L−1 of boron were 2.69 × 10−8 mol L−1 (6.40 μg L−1) and 8.15 × 10−9 mol L−1 (1.94 μg L−1), respectively, while the lower limits of quantification were 8.96 × 10−8 mol L−1 (21.33 μg L−1) and 2.72 × 10−8 mol L−1 (6.47 μg L−1), respectively. The applicability of the proposed procedure was tested using a commercial pharmaceutical formulation of NFT, and the results were compared with the procedure recommended by the British Pharmacopeia. The proposed procedure was sensitive, accurate and precise for analysis of NFT and did not require complex preparations or renovations of the electrode surface. This presents the advantage of eliminating mercury waste and minimizing the adsorptive problems related to the use of other electrodic solid surfaces.  相似文献   

20.
Pt nanoclusters were deposited in polypyrrole (PPy) nanowires by cyclic voltammetry method, fabricating a PPy-Pt nanocomposite on glassy carbon electrode (PPy-Pt/GCE). The electrocatalytic reduction of nitrite at PPy-Pt/GCE has been investigated using 0.5 M H2SO4 solution. The sensor exhibited excellent electrocatalytic activity toward nitrite reduction. In acidic medium, the cyclic voltammetry at 20 mV s− 1 gave a nitrite reduction peak at − 0.124 V with 0.566 μA μM− 1 current sensitivity in the range of 5.0 × 10− 7-1.0 × 10− 3 M. The detection limit was 1.5 × 10− 7 M (s/n = 3). The proposed method was successfully applied in the detection of nitrite in real water samples and obtained satisfactory results. The PPy-Pt composite modified electrode had good storage stability, reproducibility and anti-interference ability.  相似文献   

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