Antioxidant activity and dose enhancement factor of CeO2 nanoparticles synthesized by precipitation method

CeO2 nanoparticles (CeO2 NPs) have been considered as promising antioxidant and radioprotectant due to its mixed valence state that can prevent cell damage induced by ionizing radiation. The aim of this study is to investigate the antioxidant activity and dose enhancement factor (DEF) of CeO2. The NPs were synthesized by using a precipitation method. The structure of CeO2 NPs was characterized with an X-ray diffractometer (XRD). The antioxidant activity of CeO2 NPs was analyzed by the reduction of 1,1-diphenyl-2-picrylhydrazil (DPPH) stable free radical using UV-vis spectroscopy. The dose enhancement factor (DEF) of CeO2 NPs was examined using X-ray radiation with an energy of 6 MV. The radioprotective ability of CeO2 NPs was evaluated by mixing CeO2 NP suspension with E. coli and exposing it to X-ray radiation with a dose of 2 Gy. The XRD pattern analysis reveals that CeO2 NPs possess a cubic fluorite structure. CeO2 NPs show activity with IC50 value of 4.4 mg/ml. CeO2 NPs also show the ability to absorb X-ray radiation with DEF value < 1 and reduce the E. coli damage induced by X-ray radiation. The amount of irradiated E. coli in the presence of 0.2 mg/ml CeO2 NPs was found to be 23 times larger than that irradiated E. coli in the absence of CeO2 NPs.