Direct electrochemistry and enhanced electrocatalysis of horseradish peroxidase based on flowerlike ZnO–gold nanoparticle–Nafion nanocomposite
Direct electrochemistry and enhanced electrocatalysis of horseradish peroxidase based on flowerlike ZnO–gold nanoparticle–Nafion nanocomposite
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DOI：
10.1016/j.snb.2008.10.058
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发表时间：
2009-02
影响因子：
8.4
通讯作者：
C. Xiang;Y. Zou;Lixian Sun;F. Xu
中科院分区：
文献类型：
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作者：
C. Xiang;Y. Zou;Lixian Sun;F. Xu
我们开发了一种新的花状氧化锌-金纳米粒子（GNP）-Nafion纳米复合材料，它可以有效地促进固定在膜中的辣根过氧化物酶（HRP）的直接电子转移。循环伏安测试结果表明，HRP在磷酸盐缓冲溶液（PBS）中发生了准可逆的电化学反应，其形式电位（E0′）为−0.32V（vs. Ag/AgCl）。花状ZnO和GNP具有协同效应，ZnO-GNP-Nafion-HRP修饰电极对H2 O2的还原具有较强的电催化活性。计算的表观米氏常数（Kmapp）为1.76mM，远低于文献报道的值，表明HRP具有较高的催化活性。在1.5×10 - 5 ~ 1.1×10 - 3 M范围内，催化电流与H2 O2浓度呈线性关系，相关系数为0.998。检测限为9.0×10− 6 M（信噪比，S/N=3），表明形成的膜为酶保持其活性提供了有利的微环境。该修饰电极对H_2O_2具有快速的响应，并具有良好的稳定性和重现性。
We developed a new flowerlike ZnO–gold nanoparticles (GNPs)–Nafion nanocomposite which can promote the direct electron transfer of horseradish peroxidase (HRP) immobilized in the film effectively. The cyclic voltammetric results show that HRP entrapped in the composite could undergo a direct quasi-reversible electrochemical reaction with a formal potential (E0′) of −0.32V (versus Ag/AgCl) in phosphate buffer solution (PBS). The flowerlike ZnO and GNPs show synergistic effect and the ZnO–GNPs–Nafion–HRP modified GC electrode gives an enhanced electrocatalytic activity towards the reduction of hydrogen peroxide (H2O2). The calculated apparent Michaelis–Menten constant (Kmapp) is 1.76mM, which is much lower than that reported, indicating a high catalytic activity of HRP. The catalysis currents increase linearly to the H2O2concentration in a wide range of 1.5×10−5to 1.1×10−3M, with a correlation coefficient of 0.998. The detection limit is 9.0×10−6M (at the ratio of signal to noise, S/N=3), demonstrating that the formed film provides a favorable microenvironment for the enzyme to retain its activity. Moreover, the modified electrode displays rapid response to H2O2and possesses good stability and reproducibility.