An electrochemical biosensor for the rapid detection of DNA damage induced by xanthine oxidase-catalyzed Fenton reaction

Oxidative DNA damage is one of the most critical factors implicated in carcinogenesis and other disorders. Sensitive and reliable detection of oxidative DNA damage remains a significant challenge. In this work, a sensitive electrochemical biosensor based on a double stranded DNA immobilized on a xanthine oxidase (XOD)-modified glassy carbon electrode (denoted as DNA-XOD/GCE) has been developed to explore the rapid detection of DNA damage. Co(bpy)(3)(3+) was used as a redox indicator to monitor DNA damage induced by hydroxyl radical ((OH)-O-center dot), which is a reactive oxygen species generated by a XOD-catalyzed Fenton reaction in xanthine/FeSO4 system. The produced (OH)-O-center dot was validated by UV-vis spectroscopy. The electrochemical behavior of the underlying electrodes was characterized by square wave voltammetry and electrochemical impedance spectroscopy. Optimization of the concentrations of FeSO4 and XA, and the incubation time in terms of DNA damage was explored. Moreover, the protection of DNA from damage by antioxidants, such as ascorbic acid, aloe-emodin, and rutin was investigated. The conclusions demonstrate that the proposed electrochemical method is expected to be of use in further application for DNA damage studies, (C) 2013 Elsevier B.V. All rights reserved.