Antibacterial Bilayer Hydrogel Dressing for Effective Wound Management: Synthesis and Characterization

Nanoparticles (NPs) are widely employed in biomedicine, pharmaceuticals, and environmental remediation due to their unique properties compared to bulk materials. Silver nanoparticles (AgNPs) have attracted wide interest for wound healing because of their potent antibacterial activity. However, their incorporation into polymeric films is often limited by concerns of cytotoxicity, poor mechanical strength, and inadequate moisture balance. In this study, we developed a bilayer hydrogel film composed of polyvinyl alcohol (PVA) and chitosan, reinforced with chemically reduced AgNPs of varying sizes. The bilayer design provided a dense top layer for pathogen shielding and a hydrogel bottom layer to maintain a moist healing environment. The fabricated films exhibited high tensile strength (75 ± 1.4 MPa), remarkable swelling capacity (70.99%), excellent moisture retention (85%), and a water vapor transmission rate of 102.0 ± 2.3 g/m²·h, all critical for wound dressing performance. Antibacterial tests against Escherichia coli and Staphylococcus aureus revealed significant inhibition zones, with smaller-sized AgNPs yielding superior antibacterial efficacy. Cytotoxicity assessment using HEK-293 cells demonstrated cell viability of 85–92.2%, confirming good biocompatibility. These results highlight that controlled incorporation of AgNPs into bilayer hydrogel films can simultaneously achieve mechanical robustness, antibacterial activity, and cytocompatibility, making the material a promising candidate for next-generation wound dressings.