细胞色素c在Fe2O3修饰电极上的直接电化学和电催化特性

Direct electrochemistry of electrocatalysis of cytochrome c at Fe_2O_3 modified electrode

采用全氟磺酸树脂Nafion将金属氧化物Fe2O3颗粒细胞色素c(Cyt c)固定玻碳电极(GCE)表面,制备了Nafion-Cyt c-Fe2O3修饰的玻碳电极,构建了基于直接电子传递的过氧化氢生物传感器。在0.10mol/L pH7.0的磷酸盐缓冲溶液中,修饰电极的循环伏安曲线上显示出一对准可逆的氧化还原峰,式量电位为22mV。Cyt c在修饰电极表面的异相电子转移速率常数为1.21s-1。修饰后的电极对过氧化氢有良好响应,响应时间小于10s,电极的安培响应与过氧化氢浓度在2.0×10-6～3.0×10-3mol/L范围内成线性关系,检出限为1.0×10-6mol/L,米氏常数为1.35mmol/L,显示出较好的亲和力。

A new type of H2O2 biosensor based on the direct electron transfer was constructed by modifying Cyt c on the Nafion and Fe2O3 particles.The direct electron transfer of the immobilized Cyt c exhibited a pair of quasi-reversible redox peaks with formal potential（E^0＇） of 0.022 V（vs SCE） in 0.10mol/L pH 7.0 PBS.The electrode reaction showed a surface-controlled process with the apparent heterogeneous electron transfer rate constant（ks） of 1.21 s^-1.The electrocatalytic response showed a linear dependence on the H2O2concentration ranging from 2.0 × 10^-6 to 3.0 × 10^-3mol/L with the detection limit of 1.0 × 10^-6 mol/L at the signal-to-noise ratio of 3.The apparent Michaelis-Menten constant KMapp for the H2O2 was 1.35 mmol/L showing a high affinity.