本文构建DNA聚合酶I的新型DNA电化学传感器，将捕获探针通过Au—S键固定于Au基底表面，与互补靶序列杂交至点突变前一个碱基，通过DNA聚合酶Ⅰ将dUTP-biotin连接在目标DNA的检测位点，再与avidin-HRP反应，而后测定在TMB溶液中的电化学特性. 结果表明，DNA电化学传感电极的检测电流值与K-ras突变型基因浓度（1.0×10^-15 ~ 1.0×10^-10 mol·L^-1）对数呈良好的线性关系，且灵敏度高，特异性较佳.

In this article, we developed a novel DNA electrochemical sensor for obtaining a current-time curve based on DNA polymerase I. The capture probes were fixed on the Au electrode by Au interacting with -SH, and then hybridized with the K-ras mutant target DNA as far as one base before the mutation site. After hybridizing the K-ras mutant or wild target DNA, the resulting assembly reacted with the dUTP-biotin in the presence of DNA polymerase I. Then avidin-HRP combined the dUTP-biotin on the electrode. The proposed electrode was applied for detection in TMB solution by electrochemical technology. The experimental results showed that the detection current of the proposed DNA electrochemical sensor is proportional to the logarithmic K-ras mutant DNA concentration (1.0×10^-15 to 1.0×10^-10 mol·L^-1). It had high sensitivity and good selectivity.