Exploring the Activities of Alginate-Carrageenan@AgNPs Hydrogels Supported by Molecular Docking Studies for Potential Antimicrobial and Antioxidant Agents

Alginates and kappa-carrageenan (KC) are natural anionic biopolymers widely utilized in food, pharmaceutical, and cosmetic industries for their anticoagulant, immunomodulatory, and antiviral properties. However, unmodified sodium alginate/KC (SA/KC) hydrogels often lack sufficient antimicrobial and antioxidant efficacy, limiting their functionality in advanced biomedical and packaging applications. To overcome these limitations, we designed a multifunctional hydrogel incorporating silver nanoparticles (AgNPs) into an ascorbic acid-crosslinked SA/KC matrix. Comprehensive physicochemical, morphological, antibacterial, antioxidant, and cytocompatibility assessments were conducted. The 2% AgNPs composite exhibited pronounced antimicrobial activity against Gram-positive (L. monocytogenes, S. aureus), Gram-negative (E. coli, Salmonella sp.), and fungal strain (Candida albicans). The 2% AgNPs hydrogel was cytocompatible with normal Vero cells (IC₅₀ = 599.9 ± 3.47 µg/mL), while the 8% AgNPs variant demonstrated potent antioxidant capacity (IC₅₀ of 21.77 µg/mL and 33.3 µg/mL via DPPH and ABTS assays, respectively). Molecular dynamics simulations confirmed strong interactions between hydrogel components and key binding site residues, ensuring composite stability. These results support the potential of AgNPs-enhanced SA/KC hydrogels for antimicrobial wound dressings, bioactive drug delivery matrices, and antioxidant-active food packaging materials.