Visible light driven photodynamic anticancer activity of graphene oxide/TiO2 hybrid

Graphene oxide/TiO2 hybrid (GOT) was prepared by using Ti(OC4H9)4 and graphene oxide (GO) as reactants. Superior adsorption and photocatalysis performance under visible radiation were achieved in the presence of the GOT rather than in unmodified TiO2. GO that no toxicity in vitro acted as electron sink in GOT efficiently enhance the photodynamic activities. Consistent with photocatalytic performance of TiO2, GOT generated reactive oxygen species after visible light irradiation both in cell free condition and in vitro. No dark cytotoxicity was observed using 0–100 μg/mL GOT during long incubation time. In parallel, following exposure of cells to GOT and irradiation, a marked decrease in mitochondrial membrane potential, cell viability, activities of superoxide dismutase, catalase and glutathione peroxidase, as well as increased malondialdehyde production were observed. Moreover, GOT caused significant elevation in caspase-3 activity, and induced apoptotic death. The results indicated that GOT had excellent photodynamic anticancer activity without dark cytotoxicity.