NaOH蚀刻玻碳电极的大肠杆菌DNA电化学生物传感器的构建及检测

Preparation of an Electrochemical Biosensor Based on Sodium Hydroxide Etching Glassy Carbon Electrode and Its Detection on E. coli

以NaOH蚀刻后的玻碳电极为基底制备了高灵敏与高选择性的大肠杆菌电化学DNA传感器。经NaOH蚀刻后的玻碳电极被活化且在电极表面形成羧基层,为DNA探针的固定提供了更多位点,在偶联剂EDC/NHS的作用下,端氨修饰的探针DNA与羧基的羧氨反应使其以肽键的形式固定在电极表面,极大地提升了传感器的灵敏度。通过电化学循环伏安法(CV)和差分脉冲法(DPV)对所制备传感器的灵敏度和选择性进行表征,得到该传感器对大肠杆菌的线性检测范围为12.5~62.5 nmol/L,检出限可达1.20×10^(-9)mol/L。

A high sensitive and selective electrochemical DNA sensor for E-coli was prepared by using NaOH etched glassy carbon electrode（GCE） as the substrate.Carboxyl was brought to the surface of GCE via NaOH etching,which improved DNA probes surface density.DNA probes was immobilized on the surface of GCE through the peptide bond.The sensitivity and selectivity of the sensor were characterized by cyclic voltammetry（CV） and differential pulse voltammetric（DPV） methods.The sensor shows a high sensitive and selective response to ssDNA of E-coli,and its linear range was 12.5-62.5 nmol/L with a detection limit of 1.20×10^-9 mol/L.