麦尔多拉蓝与DNA相互作用的循环伏安法和电化学交流阻抗法研究

Cyclic Voltammetry and Electrochemical Impedance Spectroscopy on the Interaction of Meldola's Blue and DNA

应用循环伏安法及电化学交流阻抗法研究了麦尔多拉蓝(MB)分别与溶液中以及吸附在电极表面的DNA的相互作用。结果表明,MB与溶液中的DNA之间存在静电作用。分别将鲱鱼精单链DNA(ssDNA)和双链DNA(dsDNA)固定于玻碳电极(GCE)表面形成ssDNA和dsDNA修饰电极(ssDNA/GCE和dsDNA/GCE)后,求得MB在ss-DNA/GCE和dsDNA/GCE上的结合常数分别为3.4×103L.mol-1和5.2×103L.mol-1。MB与修饰在ssDNA/GCE上的ssDNA通过静电作用结合,而与吸附态dsDNA的结合为静电吸引和嵌插的共同作用。MB与ssDNA和dsDNA之间相互作用存在差异,说明MB可以作为一种有效的电化学杂交指示剂。

The interactions of Meldola＇s Blue （MB） and DNA were studied by cyclic voltammetry （CV） and electrochemical impedance spectroscopy （EIS）. A couple of cyclic vohammetric peaks of MB decreased after MB interacted with dsDNA in the solution. The interaction between MB and dsDNA was an electrostatic mode. While MB interacted with ssDNA or dsDNA modified on the glassy carbon electrode, the peak currents of MB increased and the formal potential shifted negatively. Based on cyclic voltammetry, the binding constants of MB and ssDNA or dsDNA modified on the electrodes were determined to be 3.4 ×10^3 L · mol^-1 and 5.2 × 10^3 L· mol^-1, respectively. The electrostatic interaction existed between MB and surface-immobilized ssDNA, and both electrostatic and intercalative interactions occurred between MB and surface-immobilized dsDNA, which implied that MB might be used as a potential electrochemical DNA hybridization indicator. The experimental result of EIS was in consistent with that of CV.