Voltammetric behaviour of DNA bases at a screen-printed carbon electrode and its application to a simple and rapid voltammetric method for the determination of oxidative damage in double stranded DNA

Screen-printed carbon electrodes (SPCEs) have been investigated as possible sensors to identify gamma-irradiation induced oxidative damage in double stranded (ds) DNA. Studies were undertaken to explore the possibility of using both cyclic voltammetry and differential pulse voltammetry to identify changes due to oxidative damage. Initially, guanine, adenine and 8-oxoguanosine were examined and it was found possible to differentiate them from their voltammetric responses. The voltammetric response of 8-oxoguanosine was found to be linear over the concentration range 1-400 mu M, with a slope of 0.0296 mu A mu M-1 (R-2 value of 0.9984), in the presence of 2 mM concentrations of guanine and adenine. Investigations were made into harnessing these findings to identify oxidative damage in gamma-irradiated dsDNA. The presence of oxidative damage in these samples was readily identifiable, and the magnitude of the voltammetric response was found to be dose dependant (R-2 = 0.9919). A simple sample preparation step involving only the dissolution of double stranded DNA sample in the optimised electrolyte (0.1 M acetate buffer pH 4.5) was required. This report appears to be first describing the use of a SPCE to detect DNA damage which can be related to the dose of gamma-radiation used. (c) 2006 Elsevier B.V. All fights reserved.