二茂铁及其与DNA复合物的电化学行为

在Tris-NaCl(pH=7.2)缓冲溶液中, 应用循环伏安法、微分脉冲伏安法、旋转圆盘电极实验、电化学阻抗谱等技术研究了二茂铁在旋转碳纳米管(CNT)修饰电极上的电化学行为及其与小牛胸腺DNA的相互作用. 结果表明, 二茂铁及其与双链DNA的电活性产物在静止的CNT修饰电极上均呈现一对基本可逆的氧化还原峰；在旋转电极上呈现出明显的极限扩散电流, 电化学阻抗谱呈现一个压扁的半圆. 二茂铁与DNA的作用在扩散控制过程中表现为峰电流和极限扩散电流随DNA浓度增大而减小；电化学控制过程则表现为电化学反应电阻随DNA浓度增大而增大, 条件电位下的速度常数也有一定程度的减小.

The Electrochemical Behavior of Ferrocene and Its Complex with DNA

The electrochemical behavior of ferrocene (Fc) and its interaction wit h calf thymus DNA at a rotating disk electrode modified with carbon nanotube (CN T) in Tris-NaCl buffer solution (pH=7.2) have been investigated by using cyclic voltammetry, differential pulse voltammetry, rotating disk electrode measurement , and electrochemical impedance spectrum. It is found that a pair of reversible redox waves for Fc are exhibited in the absence and presence of DNA on the immov able CNT-modified electrode. When the modified electrode is rotating, a distinct limiting diffusion current appears. Nyquist plot of Fc shows a suppressed half- circle in the absence and presence of DNA on the rotating CNT-modified electrode . Moreover, there exists an interaction of Fc with DNA under diffusion control b ased on the decrease of the peak current and limiting diffusion current with the increase of DNA concentration. On the other hand, the interaction between Fc an d DNA under electrochemical control is also studied, the results show that the e lectrochemical reaction resistance of Fc exhibiting on the rotating disk electro de increases with the addition of DNA, and the rate constant at the formal poten tial decreases in the presence of DNA compared with that in the absence of DNA.