Survey of cytotoxic and UV protection effects of biosynthesized cerium oxide nanoparticles.

Cerium oxide nanoparticles (CeO2 NPs) are among the important nanoparticles that are extensively utilized in cosmetics, automotive industries, ultraviolet (UV) filtration, gas sensors, and pharmaceutical products. In this study, CeO2 NPs were synthesized using an aqueous extract of Ziziphus jujube fruit. The synthesized nanoparticles were characterized using UV-visible spectroscopy, powder X-ray diffraction, Fourier transform infrared spectroscopy, energy-dispersive spectroscopy, field energy scanning electron microscopy, and Raman methods. The results indicated that the size of synthesized nanoparticles is between 18 and 25 nm, and they have a spherical shape. UV absorbance of the synthesized nanoparticles was measured through spectrophotometric method in the range of 290 to 320 nm. The cytotoxic activity of synthesized CeO2 NPs against colon (HT-29) cancer cell line was surveyed through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The results showed that synthesized nanoparticles are nontoxic on HT-29 cells under 400 μg/mL concentrations after 24 hours of treatment time periods. The increase in treatment time cases increases cytotoxic activity of synthesized nanoparticles. Sun protection factor of CeO2 NPs, as a criterion for amount of sunlight radiation protection, was determined by applying Mansur equation. The results demonstrated that synthesized CeO2 NPs have excellent UV protection and sunscreen physical absorption properties.