Electrochemical studies of kanamycin immobilization on self-assembled monolayer and interaction with DNA

The electrochemical characteristics of kanamycin onto self-assembled monolayer (SAM) modified gold electrode (SAM/Au) is investigated by cyclic voltammetry. In the potential range 0-0.6 V, Cu(II) yields a pair of stable redox waves at the bare gold electrode. E(pa) is located at 0.189 V and E(pc) at 0.254 V. In contrast, Cu(II) is reduced at a more positive potential and a decreasing current at the kanamycin SAM/Au electrode. Cu(II) and kanamycin can form a stoichiometry complex with chemical ratio of 2:1. The interaction of Cu(II)-kanamycin complex with calf thymus DNA is also studied in the solution. And the interactive mode between Cu(II)-kanamycin complex and DNA is verified by the fluorescence method. Binding constants (K) of the Cu(II)-kanamycin complex to DNA and binding site size (s) are calculated from voltammetric data and equal to 1.5 x 10(7) l/mol and 4 bp, respectively.