Electrochemical And Spectroscopic Studies On The Interaction Of Two Dyes With DNA

The electrochemical and spectrometric studies on the interactions of two organic dye molecules, malachite green (MG) and pyronine B (PB), with DNA have been described in this paper.There are four parts in this paper. In the first part, the development of electrochemical studies of organic molecules interactions with DNA, such as organic dyes and anticancer drugs, have been reviewed. In the second and the third parts, the interactions of malachite green with DNA have been investigated by carbon glassy electrode (GCE) and drop mercury electrode (DME), respectively. The malachite green can bind DNA and form DNA-MG complex. The formal potential of DNA-MG complex shifts negatively at the glassy carbon electrode, which is the character of an electrostatic interaction. The results of dsDNA-modified electrode suggest that the malachite green can bind DNA by two modes and the predominant interaction is intercalation interaction. Because the DNA has no significant adsorption at the GCE, the electro-reaction of malachite green binding with the outer negatively charged DNA phosphate occurs more easily at the surface of GCE than the intercalation mode, so the results of experiments at the GCE appear an electrostatic interaction of dye with DNA. The decrease of the peak current of MG after adding dsDNA was further used for the quantification of dsDNA. The linear range for dsDNA is in the range of 10.0~100.0 mg/L and the detection limit of 6.0 mg/L (3σ). Further studies of MG binding with DNA have been done by drop mercury electrode. After the addition of dsDNA into MG solution, the reductive peak current decreased with a positive shift of the peak potential, which was the typical characteristic of intercalation. The decrease of the peak current was linear with the concentration of dsDNA over the range of 0.8~12.0 mg/L and the detection limit of 0.46 mg/L (3σ).The fourth part focuses on the electrochemical properties of pyronine B (PB) and its...