Electrochemical Behaviors of Neutral Red on Single and Double Stranded DNA Modified Electrode

The interaction of neutral red (NR) with single or double stranded DNA was investigated on ssDNA or dsDNA modified gold electrode. DNA was covalently immobilized on the surface of mercaptoethanol self-assembled gold electrode through the carboxylate ester as linkage between the 5’-NH2 end of DNA and -OH group of mercaptoethanol self-assembled monolayer with the help of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS). The electrochemical behaviors of NR on DNA modified electrode were carefully investigated by cyclic voltammetry. NR was bound with ssDNA by electrostatic force but intercalation with dsDNA. The binding constant was calculated as 8.95×103 M-1 and 2.15×104 M-1 respectively. The different responses of NR with ssDNA and dsDNA were further proved by UV-Vis absorption spectrophotometry and the results suggested that NR could be served to distinguish the ssDNA and dsDNA.