Preparation, Characterization, and Antibacterial Properties of SA/PVA/RNC/ZnONPs Composite Hydrogels

SA/PVA/RNC/ZnONPs composite gel beads were prepared by calcium-mediated ionic cross-linking and freeze-drying, using sodium alginate (SA), poly(vinyl alcohol) (PVA), rape-straw-derived cellulose material (RNC) and zinc oxide particles (ZnONPs). SEM, FTIR, and XRD were used to examine the dried composite morphology, functional groups, and crystalline features. Swelling, water loss and antibacterial performance were evaluated. Among the tested formulations, 0.8 wt% PVA gave the highest reported equilibrium swelling ratio, and 1.0 wt% ZnONPs was selected on the basis of antibacterial screening. The antibacterial response against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus depended on material dosage and contact time. Antibacterial function was retained during repeated use and storage, and activity after pH preconditioning was lower at pH 1 than at pH 2–9. These observations do not establish nanoparticle immobilization, mechanical durability, or application safety. RNC loading and cross-linking conditions were fixed, so the selected formulation is not a globally optimized composition. Particle dimensions, colloidal behavior, hydrated-state mechanics, zinc release, ROS generation, and cytocompatibility require direct measurements. The material therefore represents a candidate for further investigation as an antibacterial composite, with proposed mechanisms and application suitability remaining to be validated.