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1.
Gold nanoelectrode ensembles were produced by electrodeposition using multiwalled carbon nanotubes (MWNTs) as template. A new third generation amperometric biosensor for hydrogen peroxide was developed based on adsorption of horseradish peroxidase (HRP) at the glassy carbon (GC) electrode modified with Au nanoelectrode ensembles/multiwalled carbon nanotubes/chitosan film. The resulting HRP biosensor offered an excellent detection for hydrogen peroxide at −0.11 V with a linear response range of 2.08 × 10−7 to 7.6 × 10−3 M with a correlation coefficient of 0.998, and response time <5 s. The detection limit was 1.02 × 10−7 M at 3σ. The biosensor displays rapid response, expanded linear response range, and excellent repeatability. The simple and fast fabrication of the sensor makes it superior to other techniques.  相似文献   

2.
In this paper, the hemoglobin (Hb)-collagen microbelt modified electrode with three-dimensional configuration was fabricated via the electrospinning method. Direct electron transfer of the Hb immobilized into the electrospun collagen microbelts was greatly facilitated. The apparent heterogeneous electron transfer rate constant (k(s)) was calculated to be 270.6s?1. The electrospun Hb-collagen microbelt modified electrode showed an excellent bioelectrocatalytic activity toward the reduction of H?O?. The amperometric response of the biosensor varied linearly with the H?O? concentration ranging from 5 × 10??molL?1 to 30×10??molL?1, with a detection limit of 0.37 × 10??molL?1 (signal-to-noise ratio of 3). The apparent Michaelis-Menten constant (K(m)(app)) was 77.7 μmolL?1. The established biosensor exhibited fast amperometric response, high sensitivity, good reproducibility and stability.  相似文献   

3.
A novel non-enzymatic electrochemical sensor based on a nanoporous gold electrode modified with platinum nanoparticles was constructed for the determination of hydrogen peroxide (H2O2). Platinum nanoparticles exhibit good electrocatalytic activity towards hydrogen peroxide. The nanoporous gold (NPG) increases the effective surface area and has the capacity to promote electron-transfer reactions. With electrodeposition of Pt nanoparticles (NPs) on the surface of the nanoporous gold, the modified Au electrode afforded a fast, sensitive and selective electrochemical method for the determination of H2O2. The linear range for the detection of H2O2 was from 1.0 × 10?7 M to 2.0 × 10?5 M while the calculated limit of detection was 7.2 × 10?8 M on the basis of the 3σ/slope (σ represents the standard deviation of the blank samples). These findings could lead to the widespread use of electrochemical sensors to detect H2O2.  相似文献   

4.
A facile strategy of an amperometric biosensor for hydrogen peroxide based on the direct electrocatalysis of hemoglobin (Hb) immobilized on gold nanoparticles (GNPs)/1,6-diaminohexane (DAH) modified glassy carbon electrode (GCE) has been described. A uniform monolayer film of DAH was initially covalently bound on a GCE surface by virtue of the electrooxidation of one amino group of DAH, and another amino group was modified with GNPs and Hb, successively. The fabrication process was characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). The proposed biosensor exhibited an effective and fast catalytic response to the reduction of H2O2 with good reproducibility and stability. A linear relationship existed between the catalytic current and the H2O2 concentration in the range of 1.5x10(-6) to 2.1x10(-3) M with a correlation coefficient of 0.998 (n=24). The detection limit (S/N=3) was 8.8x10(-7) M.  相似文献   

5.
A new kind of magnetic dextran microsphere (MDMS) with uniform shape and narrow diameter distribution has been prepared from magnetic iron nanoparticles and dextran. Horseradish peroxidase (HRP) was successfully immobilized on the surface of an MDMS-modified glassy-carbon electrode (GCE), and the immobilized HRP displayed excellent electrocatalytic activity in the reduction of H2O2 in the presence of the mediator hydroquinone (HQ). The effects of experimental variables such as the concentration of HQ, solution pH, and the working potential were investigated for optimum analytical performance. This biosensor had a fast response to H2O2 of less than 10 s and an excellent linear relationship was obtained in the concentration range 0.20 μmol L−1–0.68 mmol L−1, with a detection limit of 0.078 μmol L−1 (S/N = 3) under the optimum conditions. The response showed Michaelis–Menten behavior at larger H2O2 concentrations, and the apparent Michaelis–Menten constant was estimated to be 1.38 mmol L−1. Moreover, the selectivity, stability, and reproducibility of the biosensor were evaluated, with satisfactory results. Figure Amperometric response of the biosensor to successive additions of H2O2 and the plot of amperometric response vs. H2O2 concentration  相似文献   

6.
通过在金电极表面自组装L-半胱氨酸,再分别吸附纳米金与辣根过氧化物酶(HRP)的方法,成功的制备了H2O2生物传感器.采用循环伏安法考察了传感器的电化学特性,电极对H2O2在浓度为2.1×10-6~3.6×10-3 mol/L的范围内呈线性,检出限为8.9×10-7 mol/L (S/N=3).该传感器具有稳定性好,线性范围宽,检出限低等优点,同时具有一定的抗干扰能力.  相似文献   

7.
We report on a novel hydrogen peroxide biosensor that was fabricated by the layer-by-layer deposition method. Thionine was first deposited on a glassy carbon electrode by two-step electropolymerization to form a positively charged surface. The negatively charged gold nanoparticles and positively charged horseradish peroxidase were then immobilized onto the electrode via electrostatic adsorption. The sequential deposition process was characterized using electrochemical impedance spectroscopy by monitoring the impedance change of the electrode surface during the construction process. The electrochemical behaviour of the modified electrode and its response to hydrogen peroxide were studied by cyclic voltammetry. The effects of the experimental variables on the amperometric determination of H2O2 such as solution pH and applied potential were investigated for optimum analytical performance. Under the optimized conditions, the biosensor exhibited linear response to H2O2 in the concentration ranges from 0.20 to 1.6?mM and 1.6 to 4.0?mM, with a detection limit of 0.067?mM (at an S/N of 3). In addition, the stability and reproducibility of this biosensor was also evaluated and gave satisfactory results.
Figure
A novel hydrogen peroxide biosensor was fabricated via layer-by-layer depositing approach. Thionine was first deposited on a glassy carbon electrode by electropolymerization to form a positively charged surface (PTH). Negatively charged gold nanoparticles (NPs) and positively charged horseradish peroxidase (HRP) were then immobilized onto the electrode via electrostatic adsorption.  相似文献   

8.
Deposited cobalt microparticales (Co-MPs) film onto the platinum disk electrode has been successfully used as a new amperometric sensor for the determination of ascorbic acid (AA). AA is detected by surface catalyzed oxidation involving cobalt(III) oxyhydroxides in alkaline solution. The Co-MPs/Pt electrode exhibits a high electrocatalytic activity toward the AA oxidation. The diffusion coefficient of AA (6.09 × 105 cm2/s) and the catalytic rate constant (k cat = 6.27 × 103 M–1s–1) have been determined using electrochemical approaches. The amperometric response of the modified electrode is linear against the AA concentration in the range (0.01?0.48 mM). The sensor displays the best activity with a high response signal, a good sensitivity of 74.3 μA/mM, a low detection limit of 2.5 μM (signal/noise = 3) and a fast response time (<3 s). Moreover, the reproducibility, selectivity and applicability of this biosensor are satisfactorily evaluated.  相似文献   

9.
采用吸附和电化学聚合修饰方法,制得了聚亚甲基蓝-碳纳米管聚合膜玻碳电极(PMB-MWNTs/GCE),再将血红蛋白(Hb)固定在PMB-MwNTs/GCE表面,制备了稳定的Hb/PMB-MwNTs//GCE的H2O2生物传感器,并用循环伏安法对修饰电极的生物电催化行为进行了表征.研究结果表明,固定在PMB-MWNTs/...  相似文献   

10.
Thermally two-dimensional lattice graphene (GR) and biocompatibility chitosan (CS) act as a suitable support for the deposition of palladium nanoparticles (PdNPs). A novel hydrogen peroxide (H2O2) biosensor based on immobilization of hemoglobin (Hb) in thin film of CS containing GR and PdNPs was developed. The surface morphologies of a set of representative membranes were characterized by means of scanning electron microscopy and showed that the PdNPs are of a sphere shape and an average diameter of 50 nm. Under the optimal conditions, the immobilized Hb showed fast and excellent electrocatalytic activity to H2O2 with a small Michaelis–Menten constant of 16 μmol L−1, a linear range from 2.0 × 10−6 to 1.1 × 10−3 mol L−1, and a detection limit of 6.6 × 10−7 mol L−1. The biosensor also exhibited other advantages, good reproducibility, and long-term stability, and PdNPs/GR–CS nanocomposites film would be a promising material in the preparation of third generation biosensor.  相似文献   

11.
利用溶胶 凝胶法制备壳聚糖 二氧化硅有机无机复合杂化膜,用于对辣根过氧化酶进行固定,制得测定H2O2的电流型生物传感器。以1mmol/LK4Fe(CN)6作为电子媒介体。研究了各种因素如壳聚糖与二氧化硅的比率、pH、温度、工作电位等对传感器响应电流的影响。计时电流法测定H2O2的线性范围为2.0×10-6~6.8×10-4mol/L,检出限为8.0×10-7mol/L。测得酶催化动力学参数米氏常数Km=0 87mmol/L。用该法对实际样品进行了测定。  相似文献   

12.
A sulfite oxidase (SOx) purified from leaves of Syzygium cumini (Jamun) was immobilized covalently onto a gold nanoparticles (AuNPs)/chitosan (CHIT)/carboxylated multiwalled carbon nanotubes (cMWCNTs)/polyaniline (PANI) composite that was electrodeposited onto the surface of a gold (Au) electrode. A novel and highly sensitive sulfite biosensor was developed that used this enzyme electrode (SOx/AuNPs/CHIT/cMWCNT/PANI/Au) as the working electrode, Ag/AgCl as the standard electrode, and Pt wire as the auxiliary electrode. The modified electrode was characterized by Fourier transform infrared (FTIR) spectroscopy, cyclic voltammetry (CV), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS) before and after the immobilization of the SOx. The sensor produced its optimum response within 3 s when operated at 50 mVs−1 in 0.1 M phosphate buffer, pH 7.0, and at 35 °C. The linear range and detection limit of the sensor were 0.75–400 μM and 0.5 μM (S/N = 3), respectively. The biosensor was employed to determine sulfite levels in fruit juices and alcoholic beverages. The enzyme electrode was used 300 times over a period of three months when stored at 4 °C.  相似文献   

13.
Jianwen Wang  Yifeng Tu 《Talanta》2009,77(4):1454-4466
A novel disposable third-generation hydrogen peroxide (H2O2) biosensor based on horseradish peroxidase (HRP) immobilized on the gold nanoparticles (AuNPs) electrodeposited indium tin oxide (ITO) electrode is investigated. The AuNPs deposited on ITO electrode were characterized by UV-vis, SEM, and electrochemical methods. The AuNPs attached on the ITO electrode surface with quasi-spherical shape and the average size of diameters was about 25 nm with a quite symmetric distribution. The direct electron chemistry of HRP was realized, and the biosensor exhibited excellent performances for the reduction of H2O2. The amperometric response to H2O2 shows a linear relation in the range from 8.0 μmol L−1 to 3.0 mmol L−1 and a detection limit of 2 μmol L−1 (S/N = 3). The value of HRP immobilized on the electrode surface was found to be 0.4 mmol L−1. The biosensor indicates excellent reproducibility, high selectivity and long-term stability.  相似文献   

14.
A novel strategy to fabricate a hydrogen peroxide sensor based on Ag nanoparticles electrodeposited on chitosan-graphene oxide nanocomposites/cysteamine-modified gold (Au) electrode was reported. The chitosan-graphene oxide nanocomposites were first assembled on a cysteamine-modified Au electrode to produce chitosan-graphene oxide/cysteamine/Au electrode. Then Ag nanoparticles were electrodeposited on the modified Au electrode and formed Ag nanoparticles/chitosan-graphene oxide/cysteamine/Au electrode. The chitosan-graphene oxide nanocomposites and the electrodeposited Ag nanoparticles were characterized by atomic force microscopy and scanning electron microscopy. The results showed the Ag nanoparticles were uniformly dispersed on the chitosan-graphene oxide/cysteamine/Au electrode. The cyclic voltammagrams and amperometric method were used to evaluate electrocatalytic properties of the Ag nanoparticles/chitosan-graphene oxide/cysteamine/Au electrode. The results showed that the modified electrode displayed good electrocatalytic activity to the reduction of hydrogen peroxide with a detection limit of 0.7 μM hydrogen peroxide based on a signal-to-noise ratio of 3. The sensor has good reproducibility, wide linear range, and long-term stability.  相似文献   

15.
16.
Using a new phase-contrast microscopy-based method of analysis, sedimentation has recently been demonstrated to be the major mass transport mechanism of bacteria towards substratum surfaces in a parallel plate flow chamber (J. Li, H.J. Busscher, W. Norde, J. Sjollema, Colloid Surf. B. 84 (2011) 76). Here we describe a novel method for enumerating adhesion of fluorescent bacteria in a parallel plate flow chamber that allows direct imaging of the bacterial distribution along the length of the flow chamber, as caused by sedimentation. Imaging of fluorescence was done using macroscopic bio-optical imaging of the entire flow chamber, including top and bottom plates as well as of the flowing suspension in between. An algorithm is forwarded that allows to separate the fluorescence arising from the suspension and bottom plate and at the same time determines the single cell fluorescence from which the bacterial distribution over the entire bottom plate can be visualized. Enumeration of the numbers of bacteria adhering to the center of the glass bottom plate for a fluorescent Staphylococcus aureus strain was found to coincide with enumerations using phase-contrast microscopy. Moreover, due to the use of macroscopic bio-optical imaging, it was found that the number of adhering staphylococci increases linearly with distance from the inlet of the flow chamber, which could be explained from a simplified mass balance of convection, sedimentation and blocking near the bottom plate of the flow chamber.  相似文献   

17.
Wang W  Zhang TJ  Zhang DW  Li HY  Ma YR  Qi LM  Zhou YL  Zhang XX 《Talanta》2011,84(1):71-77
A novel matrix, gold nanoparticles-bacterial cellulose nanofibers (Au-BC) nanocomposite was developed for enzyme immobilization and biosensor fabrication due to its unique properties such as satisfying biocompatibility, good conductivity and extensive surface area, which were inherited from both gold nanoparticles (AuNPs) and bacterial cellulose nanofibers (BC). Heme proteins such as horseradish peroxidase (HRP), hemoglobin (Hb) and myoglobin (Mb) were successfully immobilized on the surface of Au-BC nanocomposite modified glassy carbon electrode (GCE). The immobilized heme proteins showed electrocatalytic activities to the reduction of H2O2 in the presence of the mediator hydroquinone (HQ), which might be due to the fact that heme proteins retained the near-native secondary structures in the Au-BC nanocomposite which was proved by UV-vis and IR spectra. The response of the developed biosensor to H2O2 was related to the amount of AuNPs in Au-BC nanocomposite, indicating that the AuNPs in BC network played an important role in the biosensor performance. Under the optimum conditions, the biosensor based on HRP exhibited a fast amperometric response (within 1 s) to H2O2, a good linear response over a wide range of concentration from 0.3 μM to 1.00 mM, and a low detection limit of 0.1 μM based on S/N = 3. The high performance of the biosensor made Au-BC nanocomposite superior to other materials as immobilization matrix.  相似文献   

18.
Liquid crystal cubic phase formed with monoolein has been used as immobilizing matrix to host redox protein hemoglobin on glassy carbon electrode surface. The promoted direct electron transfer between hemoglobin and electrode was observed and a large average kinetic electron transfer rate constant k(s) of 3.03(±0.02)s(-1) was estimated. The electrode modified with cubic phase containing hemoglobin retains the bioactivity of hemoglobin and shows excellent bioelectrocatalytic activity to the reduction of hydrogen peroxide with a small apparent Michaelis-Menten constant of 0.25(±0.03)mM. A novel reagentless hydrogen peroxide biosensor was constructed using the hemoglobin-containing cubic phase modified electrode and the proposed hydrogen peroxide biosensor shows a linear range of 7.0-239μM with a detection limit of 3.1(±0.2)μM and good stability and reproducibility.  相似文献   

19.
制备了一种新型有机-无机杂化材料,这种杂化材料由二氧化钛溶胶和壳聚糖组成,此杂化材料克服了普通溶胶-凝胶易脆裂的特点,可以有效地保留被包埋的 Hb 生物催化活性;而且碳纳米管和纳米铜的协同效应提高了对过氧化氢的催化性能和促进了电子的传递.研究了各种因素对传感器响应电流的影响.对过氧化氢响应线性范围 1.0×10-7~1...  相似文献   

20.
A glassy carbon electrode (GCE) was modified with gold nanoparticles (AuNPs) coated on monolayer graphene (AuNP/MG) by direct in situ sputtering of AuNPs on CVD-generated graphene. This process avoids complicated polymer transfer and polymer cleaning processes and affords AuNPs with a clean surface. The monolayer graphene is ductile and well dispersed. The clean surface of the AuNPs renders this sensor superior to GCEs modified with AuNPs on reduced graphene oxide in terms of the amperometric non-enzymatic determination of hydrogen peroxide. The detection limit is 10 nM (S/N = 3) at 0.55 V (vs. SCE), which is lower than that for similar methods, and the response time is as short as 2 s. Another attractive feature of the sensor is its feasibility for large-scale production via CVD and sputtering.
Graphical abstract Gold nanoparticles deposited onto monolayered graphene generated by chemical vapor deposition (CVD) are used for electrochemical sensing of H2O2, with the detection limit of 10 nM (S/N = 3) and response time of less than 2 s.
  相似文献   

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