Protective effect of CeO2 nanoparticles on photo-induced oxidative damage of DNA

The present paper demonstrates that inorganic ceria (CeO2) nanoparticles effectively inhibit anomalous oxidative damage of DNA induced by ultraviolet (UV) light irradiation. To utilize the CeO2 nanoparticles for the protection test of DNA, a colloidal solution of monodispersed and crystallized CeO2 nanoparticles is synthesized through a photochemical reaction of Ce(NO3)3 solution, followed by dialysis to remove unreacted electrolytes. Subsequently, the UV light induced oxidative damage of DNA in the presence or absence of CeO2 nanoparticles is evaluated by a quantitative analysis of 8-hydroxy-2¤-deoxyguanosine (8-OHdG) which is an oxidation product of guanine in base sequences. The 8-OHdG concentration in DNA is increased by the exposure to UV light. On the other hand, the co-presence of CeO2 nanoparticles diminish the formation rate of 8-OHdG. Such favorable effect of CeO2 nanoparticles is due to an excellent annihilation activity of reactive oxygen species (ROS) accounting for the DNA oxidation as well as a UV light absorption ability based on semiconducting nature.