Abstract: The natural polymer oligochitosan was modified using o-vanillin. By the excellent coordination properties of the Schiff base structure, the copper complex of o-vanillic aldehyde modified oligochitosan was prepared. Cyclic voltammetry curves indicated that Schiff basecopper complexes possessed electrochemical activity, and the reaction of central Cu²⁺ at glassy carbonelectrodes was controlled by diffusion process mechanism in the range of scan rate from 0025—
10 V/s. We investigated the mechanism of the interaction of Schiff base and Cu complex with DNA by using cyclic voltammetry, ultraviolet spectrum, viscosity and melting point method. The results show that, after adding DNA, the oxidation peak current of the complex decreases and the peak potential moves weakly. VCOSCu13,VCOSCu31 and DNA can form complexes of molar ratio of 1∶1, and the binding constants are 0.78×104,0.69×104 L/mol. The intensities of absorption peaks of complexes are reduced and the peak position appears red shift. The relative viscosity and melting point of DNA increase after adding the complex. There are interca lation action between different molar of complex and DNA.

Key words: Schiff base, Cu (Ⅱ) complex, DNA binding