基于辣根过氧化物酶放大的丝网印刷电极DNA传感器

A Screen-printed Electrode DNA Sensor Based on Horseradish Peroxidase-catalysed Amplification

以聚苯胺纳米管、壳聚糖、室温离子液体修饰的丝网印刷电极为基底电极,以辣根过氧化物酶(HRP)催化的H2O2氧化邻苯二胺(OPD)的反应作为信号放大手段,构建了一个酶放大丝网印刷DNA传感器。考察并确定了在修饰丝网印刷电极上,上述反应的最优条件及进行电化学测定的最优条件:HRP催化OPD与H2O2反应的最佳缓冲液为pH 5.0的醋酸-醋酸钠缓冲液;最佳检测支持电解质为pH 7.2的PBS缓冲液。HRP催化OPD与双氧水反应的最佳反应条件:使用16mmol.L-1双氧水和30mmol.L-1OPD反应15 min。在该传感器上,在最优条件下,DNA测定的线性范围为2×10-14mol.L-1到8×10-13 mol.L-1,回归方程为Δip=0.308 6+0.016 0 cT。通过3σ规则计算出的DNA检测限为8×10-15 mol.L-1。该传感器在DNA检测方面具有良好的选择性。

In this study, a DNA sensor was constructed based on the screen-printed electrode that was modified with polyaniline nanotubes, chitosan and room-temperature ionic liquids, and by using the horseradish peroxidase catalyzed oxidation of Hz 02 to ophenenyldiamine （OPD） as the signal amplification approach. The optimal conditions for the above-mentioned reaction and for the electrochemical determination on the modified screen-printed electrode were established as follows： the optimal buffer for the HRP-catalyzed oxidation of OPD by H2O2 was HOAc-NaOAc at pH 5.0;the optimal buffer for the electrochemical determination was PBS at pH 7.2; the best working condition for HRP-catalyzed oxidation was at a reaction time of 15 min with 16 mmol L^-1 H202 and 30 mmol · L^-1 OPD. Under these optimal conditions, DNA can be determined in a linear range from 2×10^-14 mol · L^-1 to 8×10-13 mol· L^-1 , with a regression equa- tion △ip=0. 308 6＋0. 016 Oct. The detected limit was found to be 8×10-15 tool· L^-1 according to 30 rule. Good selectivity against mismatched DNAs was verified.