基于纳米金和硫堇固定酶的过氧化氢生物传感器

在铂电极上自组装一层纳米金(GNs), 构建负电荷的界面, 然后通过金-硫、金-氮共价键合作用和静电吸附作用自组装一层阳离子电子媒介体硫堇(Thio). 再以同样的作用自组装一层GNs和辣根过氧化酶(HRP)的混合物, 最后在电极最外层滴加一层疏水性聚合物壳聚糖(Chit), 由此制备了一种新型的过氧化氢生物传感器. 研究了工作电位、检测底液pH、温度对响应电流的影响, 以及GNs和HRP之间的相互作用, 探讨了传感器的表面形态、交流阻抗、重现性和稳定性. 该传感器的酶催化反应活化能为12.4 kJ/mol, 表观米氏常数为6.5×10^－4 mo/L, 在优化的实验条件下, 所研制的传感器对H₂O₂的线性范围为5.6×10^－5～2.6×10^－3 mol/L, 检出限为1.5×10^－5 mol/L. 应用此方法制备了HRP和葡萄糖氧化酶(GOD)双酶体系葡萄糖生物传感器, 并应用于实验样品葡萄糖含量的测定.

Hydrogen Peroxide Biosensor Based on Immobilizing Enzyme by Gold Nanoparticles and Thionine

A hydrogen peroxide biosensor has been presented in this paper. Gold nanoparticles (GNs) was self-assembled onto a platinum electrode to form a negatively charged surface, and cationic dye-thionine (Thio) was linked by Au—S and Au—N covalent bond and electrostatic adsorption as an electron transfer mediator. The mixture of GNs and horseradish peroxidase (HRP) was assembled on the electrode at the same procedure, and chitosan (Chit) was dropped onto the electrode surface to fabricate a novel hydrogen peroxide biosensor. The effects of applied potential, pH and temperature on the response currents have been investigated. The surface configuration, electrochemical impedance, reproducibility and stability have also been researched. Activation energy for enzymatic reaction of the biosensor was 12.4 kJ/mol, and the appar-ent Michaelis-Menten constant was 6.5×10^－4 mo/L. And the linear range of the biosensor was from 5.6×10^－5 to 2.6×10^－3 mol/L with a detection limit of 1.5×10^－5 mol/L. The method has been applied to construct a bienzyme-based biosensor of HRP and glucose oxidase (GOD) for the determination of glucose.