Eco-friendly Fabrication of CeO2 Nanoparticles with Solanum nigrum: A Study on Cytotoxicity and Photocatalysis with plant growth studies

The synthesis of cerium oxide nanoparticles (CeO ₂ -NPs) has been carried out using a sol-gel method, in which Solanum nigrum ( S. nigrum) extract was used as the stabilizing agent. The nanoparticles were characterized by XRD, FE-SEM, EDX, UV-Vis and XPS methods. The XRD pattern exhibits the cubic structure. The FESEM/PSA pictures have shown the agglomerated morphology of CeO ₂ -NPs. The chemical bonding nature of CeO ₂ nanoparticles was examined using the XPS technique, which showed that Ce, O, and Ag make up the majority of the sample. Spin-orbit doublets and a well-separated spin-orbit splitting are visible in the high-resolution Ce 3D spectra. Lattice and surface adsorbed oxygen ions are associated with the three primary binding energies. The C 1S peak indicates the presence of organic carbon. The UV-Vis spectra for the nanoparticles exhibit a prominent adsorption band at the wavenumber region of 417 nm. Moreover, the photocatalytic efficiency of CeO ₂ -NPs has been examined by carrying out the degradation of RB dye under UVA light showing the degradation percentage of 78%, which are linked to contaminants found in sewage water. The MTT assay results have indicated that the cytotoxicity of CeO ₂ -NPs on HeLa cell lines is not concentration-dependent. Additionally, the cytotoxicity analysis shows a significant toxicity for the higher concentration of 200 µg/mL for the cancer cells against the nanoparticles. The study found significant differences in the effects of CeO ₂ NPs on seed weights, root and shoot lengths, and both. Plants treated with a 10 ^⁻4 M dose had longer shoots and roots, while those treated with 5a had significantly larger seeds.