Facile green synthesis of gelatin sodium alginate cerium oxide hydrogel nanocomposite and their photocatalytic and its biological applications

In this study, we harnessed the potential of a plant extract derived from Oldenlandia umbellata, a member of the Rubiaceae family, as a biological reducing agent to create cerium oxide nanoparticles from cerous nitrate hexahydrate. These cerium oxide nanoparticles, in turn, were incorporated into hydrogels composed of gelatin and sodium alginate, resulting in the formation of Gelatin–Sodium Alginate–Cerium Oxide (GSCeO₂) nanocomposite hydrogels. UV–visible spectra displayed absorbance peaks at 340 nm and 361 nm for cerium oxide nanoparticles and GSCeO₂ nanocomposites, respectively. Fourier-Transform Infrared (FT-IR) spectroscopy was employed to differentiate between various functional groups present in the cerium oxide nanoparticles and GSCeO₂ nanocomposites. X-ray Diffraction (XRD) investigations confirmed the face-centered cubic structure with a sharp peak at the (111) plane for both cerium oxide nanoparticles and GSCeO₂ nanocomposites. Furthermore, XRD analysis provided the average particle sizes of 16.7 nm and 21.39 nm for 0.1 M cerium oxide nanoparticles and GSCeO₂ nanocomposites, respectively. Energy-Dispersive X-ray Analysis confirmed the presence of essential elements in the nanoparticles and nanocomposites. The GSCeO₂ nanocomposites exhibited excellent photocatalytic activity against methyl red dye under exposure to ultraviolet–visible light irradiation and demonstrated enhanced antioxidant properties. In vitro cytotoxicity assays conducted on MDA-MB 231 (human breast cancer cells) revealed an IC50 value of 28.69 µg/ml for GSCeO₂ nanocomposites. Additionally, GSCeO₂ nanocomposites displayed potent antifungal activity against Aspergillus flavus and Candida albicans.