Sensitive detection of H2O2 and H2O2-related reactant with Ru(bipy)2(7,8-dimethyl-dipyridophenazine)2+ and oligodeoxyribonucleotide

A sensor for H2O2 and H2O2-related reactant was constructed with oligonucleotides and Ru(bipy)2dppx2+ (bipy = 2,2′-bipyridine, dppx = 7,8-dimethyl-dipyridophenazine), which was performed by converting the H2O2-induced DNA cleavage into the change of luminescence. The ‘DNA light switch’ Ru(bipy)2dppx2+ could emit strong luminescence in the presence of dsDNA. DNA cleavage occurred upon addition of H2O2 due to the Fenton reaction, which resulted in the decrease of the luminescence of Ru(bipy)2dppx2+. Therefore, the luminescence intensity depended on the concentration of H2O2 and H2O2-related reactants, and the detection limits for H2O2, uric acid and cholesterol were 0.20 μM, 0.46 μM and 1.25 μM, respectively. The recovery varied between 94.0% and 105.0% when the assay was applied to the determination of uric acid and cholesterol in biological samples, which demonstrated the good practicability of the assay.