Electrochemical detection of in situ DNA damage induced by enzyme-catalyzed Fenton reaction. Part II in hydrophobic room temperature ionic liquid

A hydrophobic room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), was applied as nonaqueous solvent for the generation of hydroxy radical (.OH) through glucose oxidase-catalyzed Fenton reaction. The enzyme catalyzes the oxidation of glucose, and the produced H2O2 further reacts with transition metal ions, generating hydroxyl radicals. They attacked DNA and led its damage. This was detected by square wave voltammetry (SWV) of the electroactive indicator Co(bpy)33+. It bound more strongly to intact DNA, and the SWV peak currents decreased at the potential of 0.064 V when DNA was damaged. The experimental results testified that the antioxidants, ascorbic acid, aloe-emodin and rutin, inhibited oxidative DNA damage by hydroxyl radicals. The method is promising for rapid, sensitive, and inexpensive detection of DNA damage. (author)