The primary object is to investigate the interaction between DNA and 5-fluorouracil (5-FU) in the light of DNA modified electrode based on covalent assembly by the potential control. The cyclic voltammetry and square wave voltammetry, along with ultraviolet-visible absorption spectrometry, proved to be a powerful technique for the elucidation of interaction between DNA and 5-fluorouracil with methylene blue (MB) as electroactive indicator. The results indicated that the peak potential shifts negatively with the increase of the scanning rate. The ratio of anodic current to the cathodic current decreased with the decrease of the scanning rate. The mechanism of the electrode is coupling electrochemistry-chemistry. The interaction between MB and DNA is electrostatic interaction, while the interaction between 5-FU and DNA is intercalative. These studies are very important for the design of DNA-targeting drugs in the hereditary engineering.

Key words: DNA self-assembly, potential control, gold electrode, 5-fluorouracil