硫堇与DNA分子相互作用的电化学方法研究

An Electrochemical Study on the Interaction between Thionine and DNA

采用交流阻抗技术和循环伏安法 ,研究了在硫堇自组装膜修饰金电极上 ,以及在硫堇或DNA吸附修饰的玻碳电极上 ,硫堇与DNA分子的相互作用;硫堇自组装膜修饰金电极与DNA分子作用后 ,阻抗增大 ,表明它们之间发生了作用 ;吸附在玻碳电极上的硫堇 (DNA)与DNA(硫堇 )作用后 ,峰电位和峰电流均发生了变化 ,结合光谱测定结果 ,表明硫堇与DNA分子间存在着嵌插、静电等作用 ,二者作用的反应速度与分子在电极上固定的位置有关;在PBS缓冲液中硫堇 -DNA的表观结合常数为4.9×104L·mol -1 ;交流阻抗技术和循环伏安法是研究小分子与DNA分子间相互作用的经济、快速。

The interaction of thionine with DNA was studied by cyclic voltammetric and a.c. impedance methods. As a consequence of the interaction between thionine and DNA, an increment in impedance was observed for the thionine _ modified self _ assembled gold electrode as well as for the thionine _ or DNA _ modified glassy carbon electrodes. Changes in peak potential and peak current occurred, after the adsorbed thionine reacted with DNA adsorbed on glassy carbon electrodes. Our spectroscopic results suggest that intercalation and electrostatic forces bind thionine and DNA molecule up in PBS buffer. The apparent equilibrium constant was found to be 4.9×104 L·mol-1. The reaction rate between thionine and DNA depends upon their anchor sites on the electrode. Thionine _ modified gold electrodes were prepared by a self _ assembly technique, whereas DNA _ and thionine _ modified carbon electrodes were obtained by adsorption. Both cyclic voltammetry and electrochemical impedance method have been proved to be cheap, rapid and simple methods for the characterization of interactions between small molecules and DNA.