Binding reactions of copper(II) complexes of 1,10-phenanthroline (phen) and tetraaza macrocyclic ligand TAAB with calf thymus DNA have been investigated voltammetrically at bare and DNA modi®ed glassy carbon electrodes. The values of binding constant, binding site size, ratio of binding constants for the reduced and oxidized copper complex forms as well as information on the electrostatic and intercalative binding modes were obtained by solution and surface-based methods. The Cu(phen) 2 2 complex mediates the dsDNA cleavage to a higher degree than Cu(TAAB) 2 as indicated by the redox marker Co(phen) 3 3and the anodic signal of the DNA base. A procedure for the damage to DNA detection using dsDNAaGCE biosensor is proposed.

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Nanostructured films were deposited at the surface of working electrode of the screen-printed assembly and utilized for the surface modification with double-stranded DNA. The basic electrochemical properties of the sensors were investigated using voltammetric methods. Modified electrodes were also characterized by scanning electron microscopy and electrochemical impedance measurements. It was found that the electrode modification with DNA and nanomodifier leads to an enhanced sensitivity of the DNA voltammetric detection. New potentialities of the utilization of the K 3 [Fe(CN) 6 ] cyclic voltammetric signal and electrochemical impedance spectroscopy were found. The DNA-based biosensors showed good repeability and necessary stability within several days.

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