利用电化学技术对玻碳电极表面进行活化,然后再利用偶联活化剂将氨基修饰的军团菌特异基因序列探针ssDNA固定到活化后的玻碳电极表面,构建军团菌DNA电化学生物传感器。利用电化学交流阻抗技术对构建的军团菌DNA电化学生物传感器性能进行表征及优化。结果表明:构建军团菌DNA电化学生物传感器可通过杂交前后阻抗信号的变化,有效识别互补军团菌DNA片段。在优化试验条件下,可实现对人工合成军团菌特异性基因的检测。杂交前后阻抗差值与靶标链DNA浓度在5.0×10-9~2.5×10-8mol·L-1范围内呈线性关系,检出限(3S/N)为1.0×10-9mol·L-1。

The surface of glassy carbon electrode (GCE) was first activated by electrochemical technique, and then immobilized with legionella′s specific gene sequence probe ssDNA, which has been modified with aminogroup by coupling activator. Thus, the electrochemical biosensor for determination of the leginonella′s DNA segment was fabricated and its properties were characterized and optimized by using electrochemical AC impedance technique. As shown by the experimental results, the complementary legionella′s DNA segments were effectively recognized by the change of impedance signals given by the biosensor before and after hybridization. Under optimum conditions, linear relationship between the values of increase in impedance value (ΔR) and the concentration of the DNA target standard strand was obtained in the range of 5.0×10-9-2.5×10-8mol·L-1, with value of detection limit (3S/N) of 1.0×10-9mol·L-1.