Abstract
In this paper, the anti-cancer drug 6-mercaptopurine (6-MP) was taken as the detection object. The biosensor of dsDNA/GNs/chit/GCE was established using the grapheme (GNs) and chitosan (chit) as the compound modified material. The electrochemical behavior of 6-MP on the sensor was discussed, and the damage and its mechanism of 6-MP on DNA were studied. The experimental result showed that, after the modification of GNs-chit, the electrode activation area of GNs/chit/GCE increased remarkably, which was improved from 1.76cm2 to 8.64 cm2, and the responsive oxidation peak current of GNs/chit/GCE to K3[Fe(CN)6] also increased remarkably. At the meantime, it was demonstrated that DNA was effectively fixed on the GNs/chit/GCE electrode;6-MP caused obvious damage to dsDNA, and the damage degree on the adenine was bigger than that on the guanine; the interaction between 6-MP and dsDNA was preliminarily deduced as the intercalation, and its electrochemical oxidation process was an irreversible process controlled by the adsorption.