Cerium oxide nanoparticles prepared through Bio-combustion using Ficus carica as effective antioxidant, anticancer and dye degrading agent

The rising levels of environmental contamination and oxidative stress disorders have led to a growing demand for multifunctional nanomaterials that possess both biomedical and catalytic importance. CeO₂ nanoparticles (NPs) were synthesized using a green solution combustion method involving Ficus carica F. extract, followed by an evaluation of their structural, biological, and photocatalytic properties. XRD confirmed a pure cubic fluorite phase (Fm-3m) with a crystallite size of 11.3 nm, which was also validated through Williamson-Hall and Rietveld refinements (χ² = 1.9). FTIR spectroscopy revealed strong Ce-O vibrational modes at 955 cm^-1, and a bandgap of 3.03 eV was determined through DRS. The SEM/TEM images displayed spherical, agglomerated particles with an average diameter of 13.5 nm. The BET analysis revealed a surface area of 30.081 m²/g, a pore radius of 1.374 nm, and a pore volume of 0.057 cm³/g, confirming the presence of microporosity. The analysis via XPS validated the existence of Ce, O, and C, revealing the coexistence of Ce³⁺/Ce⁴⁺ oxidation states alongside surface hydroxyl species. CeO₂ NPs exhibited a dose-dependent redox activity that resulted in a reduction of cell viability to 48.82% at a concentration of 50 µM. H₂O₂ enhanced LDH release to 223.86%, whereas CeO₂ NPs (1-7.5 µM) reduced it to 124.84%, demonstrating redox cycling antioxidant protection. Fluorescence imaging showed dose-dependent duality-antioxidant at low, pro-oxidant at high-consistent with mitochondrial damage and ATP depletion. Furthermore, CeO₂ NPs demonstrated a remarkable 94.9% degradation of methylene blue under visible light, indicating their significant potential for both therapeutic and environmental applications.