In order to investigate the genotoxicity of Cu2O nanocubes, a novel electrochemical biosensor was constructed by incorporating the mixture of Cu2O nanocubes and Au nanoparticles (AuNPs) into a multi-membrane containing natural ds-DNA. The ds-DNA was damaged in situ in the membrane and the DNA damage was monitored by DPV with two electrochemical indicators, Co(phen)(3)(3+) and Ru(NH3)(6)(3+). The mechanism studies showed that the nanoCu(2)O and AuNPs had synergistic effects on DNA damage and the DNA damage reagent ((OH)-O-center dot) was generated via electro-Fenton (E-Fenton) reactions on the surface of Cu2O nanocubes and Au nanoparticles. This method was very suitable to study the genotoxicity mechanisms of nanomaterials and it had potential application in studying some chemicals anti-oxidation property. (C) 2011 Elsevier Ltd. All rights reserved.