Nickel-doped cerium oxide nanoparticles: biosynthesis, cytotoxicity and UV protection studies

This study was conducted to obtain Ni x Ce1-x O₂ (where x = 0, 1, 3 and 5% w/w) nanoparticles using Salvadora persica extracts through an easy, inexpensive and non-toxic method. The biosynthesized nanoparticles have been characterized via powder X-ray diffraction (PXRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) spectroscopy, and vibrating-sample magnetometer (VSM) analysis. The results of PXRD showed that Ni doping in the CeO₂ process generated a higher shift at an angle of (111); also, the PXRD patterns were surveyed by the Rietveld refinement technique. Raman analysis revealed that doping nickel in CeO₂ led to the nanoparticles reducing the intensity of the F2g mode. The FESEM images showed that the particle size was 5-6 nm and it had a spherical shape. The hysteresis loops of the synthesized nanoparticles were similar to that of the normal ferromagnetic materials. The cytotoxic activity of the synthesized undoped and Ni-doped CeO₂-NPs was determined using MTT assays against a colon cancer cell line (HT-29). The results showed that the cytotoxic effect of the synthesized nanoparticles changed after doping nickel in CeO₂-NPs. The increase in the Ni-doping value for CeO₂-NPs increased the cytotoxic activity. The sun protection factor (SPF) has been estimated through spectrophotometric measurements for determining UV protection. This showed that increasing the percentage of nickel in the doped nanoparticles increased the protection factor and a higher SPF value was obtained: 48.52.