DNA interaction of some polymer–copper(II) complexes containing 2,2′-bipyridyl ligand and their antimicrobial activities

The water soluble polymer–copper(II) complex samples, [Cu(bpy)2(BPEI)]Cl2 · 4H2O (bpy = 2,2′-bipyridine, BPEI = branched polyethyleneimine), with varying degrees of copper(II) chelates content in the polymer chain, were prepared by ligand substitution method in water–ethanol medium and characterized by Infra-red, UV–visible, EPR spectral and elemental analysis methods. The interaction of these polymer–copper(II)–bipyridyl complex samples with calf thymus DNA has been explored by using electronic absorption spectroscopy, emission spectroscopy and gel electrophoresis techniques. The observed changes in the physico-chemical features of the polymer–copper(II) complex on binding to DNA suggest that the complex binds to DNA with electrostatic interaction mode. A sample of polymer–copper(II) complex was tested for its antibacterial and antifungal activity and it was found to have good antibacterial and antifungal activities.