DNA interaction of [Cu(dmp)(phen-dion)] (dmp = 4,7 and 2,9 dimethyl phenanthroline, phen-dion = 1,10-phenanthroline-5,6-dion) complexes and DNA-based electrochemical biosensor using chitosan–carbon nanotubes composite film

Abstract

The interaction of two new water-soluble [Cu(4,7-dmp)(phen-dione)Cl]Cl (1) and [Cu(2,9-dmp)(phen-dione)Cl]Cl (2) which dmp is dimethyl-1,10-phenanthroline and phen-dion represents 1,10-phenanthroline-5,6-dion, with DNA in solution and immobilized DNA on a chitosan–carbon nanotubes composite modified glassy carbon electrode were investigated by cyclic voltammetry and UV–Vis spectroscopy techniques. In solution interactions, spectroscopic and electrochemical evidences indicate outside binding of these complexes. To clarify the binding mode of complexes, it was done competition studies with Hoechst and Neutral red as groove binder and intercalative probes, respectively. All these results indicating that, these two complexes (1) and (2) interact with DNA via groove binding and partially intercalative modes, respectively. The electrochemical characterization experiments showed that the nanocomposite film of chitosan–carbon nanotubes could effectively immobilize DNA and greatly improve the electron-transfer reactions of the electroactive molecules that latter finding is the result of strong interactions between captured DNA and Cu complexes. This result indicates that these complexes could be noble candidates as hybridization indicators in further studies. At the end, these new complexes showed excellent antitumor activity against K562 (human chronic myeloid leukemia) cell lines.