Electrochemical Detection of <i>anti</i>-Benzo[<i>a</i>]pyrene Diol Epoxide DNA Damage on <i>TP53</i> Codon 273 Oligomers

Abstract

DNA damage from (+/-)-anti-benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE) at a hotspot TP53 gene sequence was electrochemically detected. BPDE was exposed to gold electrode immobilized double-stranded DNA oligomers followed by voltammetric measurements in the presence of redox-active C(12)H(25)V(2+)C(6)H(12)V(2+)C(12)H(25) (V(2+) = 4,4'-bipyridyl or viologen, C12-viologen). Square wave voltammograms from BPDE-exposed DNA-modified electrodes showed the emergence of a C12-viologen-DNA complex at -0.37 V versus Ag/AgCl. The peak current intensity of this redox wave was dependent on both BPDE concentration and exposure time. Controls with alternate xenobiotics and DNA sequences showed this redox wave to be primarily due to BPDE damage at the wild-type DNA sequence. The detection limit was determined to be approximately 170 nM BPDE. Mass spectrometry and UV thermal melting experiments provided insight into the BPDE reaction and mirrored the sensor results. This report demonstrates that an electrochemical hybridization sensor can be used to detect sequence-related xenobiotic DNA damage.