Layer-by-layer assembly of graphene, Au and poly(toluidine blue O) films sensor for evaluation of oxidative stress of tumor cells elicited by hydrogen peroxide

High level of oxidative stress is involved in formation of incipient tumor and carcinomatous cells. Here in this contribution we have explored a facile strategy to assess the oxidative stress elicited by hydrogen peroxide (H₂O₂) in cells with amperometric current-time technique in vitro. An electrochemical biosensor exhibiting high sensitivity and selectivity to H₂O₂ is fabricated by integration of graphene with gold nanoparticles and poly(toluidine blue O) films. The efflux of H₂O₂ from several representative tumor cells and normal cells on exposure to ascorbic acid could be detected by using the graphene-based nanocomposite films. The results indicate that tumor cells release much more H₂O₂ than do the normal cells. The novel sensor raises the possibility for clinical diagnostic application to evaluate the higher level of intracellular oxidative stress of tumor cells in comparison with normal cells.