Multifunctional antibacterial and antioxidant hydrogel based on modified sodium alginate and green-synthesized Ag NPs for wound dressing applications

• A novel bio-nanocomposite hydrogel with enhanced antibacterial, antioxidant, and wound healing properties. • Ag NPs stabilized with Calendula officinalis extract ensure eco-friendly, biocompatible synthesis. • Potent antibacterial effects against both Gram-negative and Gram-positive bacteria. • High cytocompatibility, blood compatibility, and hemostatic properties, suitable for wound healing. Wound healing is a complex biological process that requires effective materials to restore skin integrity. The objective of this study was to develop a bio-nanocomposite hydrogel with antibacterial, antioxidant, and hemostatic functions for wound healing applications. Sodium alginate (SA) was sequentially modified through dialdehyde and dicarboxylate functionalization and co-polymerized with acrylamide (AAm) and acrylic acid (AA) using potassium persulfate (KPS) as the initiator and N, N -methylene bisacrylamide (MBA) as the crosslinker. Silver nanoparticles (Ag NPs) were green-synthesized using Calendula officinalis (CO) extract and incorporated into the hydrogel. The prepared hydrogel showed a swelling capacity of 6700 % within 2 h and underwent controlled biodegradation under physiological conditions. Antibacterial tests demonstrated inhibition zones of 27 mm against Escherichia coli and 28 mm against S. aureus . The hydrogel also displayed 73 % antioxidant activity, 98 % cell viability in HFF-2 cells, a hemolysis index below 2 %, and a hemostatic index of 25 %. These results indicate that the hydrogel has potential for supporting wound healing through its combined antibacterial, antioxidant, and hemostatic properties.