中文摘要：

用电化学氧化法使玻碳电极表面氧化生成羧基，利用偶联活化试剂将1.0G树状高分子（PAMAM）固定在玻碳电极表面，并通过共价结合固定ssDNA。以亚甲基蓝为指示剂，采用循环伏安法、示差脉冲伏安法等电化学方法对DNA电化学生物传感器进行了表征。结果发现，通过亚甲基蓝与双链dsDNA作用的氧化还原电流的变化，可以识别和定量检测溶液中互补的ssDNA片段。经过条件优化，本法测定DNA的浓度线性范围为2×10^-9－2×10^-7mol／L，检出限为1×10^-9mol／L。

英文摘要：

The carboxy on GCE surface was obtained by electrochemical oxidation, and 1.0 G polyamidoamine dendrimer （PAMAM） was immobilized on the electrode by coupled activation agent, then ssDNA was also immobilized through covalently action. Using methylene blue as the indicator, the DNA electrochemical biosensor was characterized by electrochemical methods such as cyclic vohammetry and differential pulse voltam-merry. The results indicated that the complementary ssDNA segment in the solution could be recognized and detected through mensurating the oxidation-deoxidation peak current of embed methylene blue in dsDNA. The linear range for the determination of target DNA was 2×10^-9-2×10^-7mol/L, and the detection limit was 1×10^-9 mol/L.