DNA oxidation mediated by [Ru(bpy)2tatp]2+ upon incorporation of [Co(phen)3]3+

The electrochemical oxidation of DNA mediated by [Ru(bpy)2tatp]2+ (bpy = 2,2′-bipyridine, tatp = 1,4,8,9-tetra-aza-triphenylene) upon incorporation of [Co(phen)3]3+ (phen = 1,10-phenanthroline) has been investigated. The results from emission spectra and fluorescence microscope images suggest the formation of an aggregate containing [Ru(bpy)2tatp]2+, DNA and [Co(phen)3]3+ based on the strong interactions. The evidences from repetitive differential pulse voltammograms and cyclic voltammogams reveal that the presence of [Co(phen)3]3+ can promote the oxidation of DNA mediated by [Ru(bpy)2tatp]2+ on an indium tin oxide (ITO) electrode. The oxidative response of DNA shows a cumulative enhancement with increasing the voltammetric sweeping number, and a stable linear response to DNA is found between 0.001 mM and 0.1 mM. Furthermore, the oxidative mechanism of DNA mediated by [Ru(bpy)2tatp]2+ upon incorporation of [Co(phen)3]3+ becomes evident, depending on the concentration of DNA and mediators, the structure of mediators and scan rate. The results from this study provide a significant basis for better understanding the oxidative damage of DNA mediated by DNA-binding agents.

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► Co(III) complexes weaken DNA-promoted assembly of [Ru(bpy)2tatp]2+ on ITO electrodes.
► Co(III) complexes promote Ru(II)-mediated oxidation of DNA.
► Oxidative response of DNA shows a linear range from 0.001 to 0.1 mM.