Eco‐Friendly ZnO–Chitosan Nanocomposite‐Embedded Sodium Alginate/Polyvinyl Alcohol/Saffron Hydrogel for Enhanced Antibacterial Applications

This study reports the green synthesis, development, and characterization of novel eco‐friendly zinc oxide nanoparticles (ZnO NPs) coated with chitosan (ZnO NPs–Chsn) and their incorporation into a polyvinyl alcohol/sodium alginate/saffron (PSS) hydrogel for enhanced antibacterial applications. ZnO NPs were biosynthesized using quince ( Cydonia oblonga ) peel extract, yielding semi‐spherical particles with an average size of ~72 nm. The Chsn coating improved particle dispersion, surface uniformity, and colloidal stability while modifying the surface charge (zeta potential from −27 to −11.6 mV), thereby enhancing biocompatibility and antibacterial potential. The ZnO NPs–Chsn were integrated into the PSS hydrogel matrix via a freeze–thaw method to improve biocompatibility and generate a highly porous structure. Incorporation of ZnO NPs–Chsn increased the maximum swelling ratio from 220.91% ± 1.89% (PSS) to 589.39% ± 1.77% and enhanced hydrophilicity, as confirmed by contact angle (CA) measurements. Antibacterial assays (disc diffusion) showed that the PSS/ZnO NPs–Chsn hydrogel produced inhibition zones of 4.64 ± 0.20 mm ( S. aureus ), 1.55 ± 0.10 mm ( E. coli ), and 4.94 ± 0.14 mm ( B. cereus ), compared with negligible inhibition for the base PSS hydrogel. The enhanced antibacterial effect is attributed to the synergistic action of ZnO NPs and Chsn through bacterial membrane disruption, reactive oxygen species (ROS) generation, and metabolic impairment, potentially boosted by the bioactive compounds in saffron (crocin and safranal). These findings highlight the potential of PSS/ZnO NPs–Chsn hydrogels as eco‐friendly antibacterial biomaterials; however, further evaluations are required to confirm clinical applicability.