肌醇六磷酸钙膜固定辣根过氧化酶制备过氧化氢生物传感器

Hydrogen peroxide biosensor based on immobilization of horseradish peroxidase in calcium phytate matrix

利用肌醇六磷酸钙（Ca-IP6）的磷酸酯键及Ca^2＋对HRP具有静电吸引和螫合作用，将其自组装于玻碳电极（GCE）表面，制备Nafiort／HRP／Ca—IP6／GCE生物传感器。用紫外。可见吸收光谱、电化学阻抗光谱和循环伏安法对Nafion／HRP／Ca—IP6／GCE膜进行了表征。实验结果表明，吸附了HRP仍然能够保持原有的生物活性，实现了辣根过氧化物酶在电极表面的直接电子转移。该修饰电极对过氧化氢有很好的电催化活性，线性范围为2．67×10-7-1．067×10^-6mol／L，最低检测限为1．3×10^-7mol／L（信噪比S／N=3），米氏常数为0．259mmol／L。该生物传感器拥有较低的检测限，较高的电催化效率和较好的稳定性及重现性。

A novel composite electrode of Nafiort/HRP/Ca-IP6/GCE has been constructed for the electro- chemical detection of H202. Nafion/HRP/Ca-IP6/GCE was characterized by UV-vis absorption spectroscopy, cyclic voltammetry （CV） and electrochemical impedance spectroscopy （EIS）. Experimental results showed that the absorbed HRP retained its bioactivity and realized direct electron transfer due to the improved biocompatibility of calcium phytate. Moreover, the biosensor displayed excellent bioelectrocatalytic ability toward the reduction of H2O2 with a linear response to H2 02 over a coneentration range from 2.67 × 10 ^-7 to 1. 067 × 10 ^ -6 mol/L, the detection limit was 1.3 × 10 ^-7 mol/L（ S/N = 3）, and a constant KM^app was 0.259 mmol/L. The biosensor exhibited low detection limit, high enzymatic activity and good repro- ducibility and stability.