Green synthesis, characterization, photocatalytic activity, and biological applications of gelatin-sodium alginate zinc oxide nanocomposite

Abstract

The present study stated a green approach for synthesizing zinc oxide nanoparticles using Oldenlandia umbellata (Rubiaceae) plant extract, which was used as the biological reducing agent for synthesizing zinc oxide nanoparticles from zinc nitrate hexahydrate. The synthesized ZnO nanoparticles were loaded with Gelatin-Sodium alginate biopolymers to convert them into Gelatin-Sodium alginate-Zinc oxide (GSZnO) nanocomposite hydrogels. The UV–Visible spectroscopy showed maximum absorbance at 376 nm for ZnO Nanoparticles and 360 nm for GSZnO nanocomposite. Different functional groups in ZnO Nps and GSZnO nanocomposites are identified using FT-IR spectroscopy. The SEM analysis of ZnO Nps and GSZnO nanocomposites demonstrates the size in the range of 67–80 nm. DLS Particle size analysis shows 71 nm for ZnO.A NPs and 74 nm for GSZnO nanocomposites. XRD analysis proved the crystalline nature and sharp highest peak at 101) plane confirm the hexagonal shape. While the EDAX analysis confirmed the formation of zinc oxide in the nanoparticles. Antioxidant studies were carried out for ZnO.A Nps showed better antioxidant properties compared to plant extract. The antimicrobial activity of plant extract and ZnO.A Nanoparticles were done against Staphylococcus aureus, Proteus vulgaris, Aspergillus flavus, and Candida albicans. ZnO.A nanoparticles showed good photocatalytic activity of methylene red dye in the presence of visible light irradiation. GSZnO nanocomposite was studied for In-vitro cytotoxicity on Vero cells, The IC50 value for the GSZnO nanocomposite was 101.5 µg/ml.