Development and Evaluation of Kelakai Leaf Extract–Mediated Silver Nanoparticle Hydrogel for enhanced Antibacterial and Antibiofilm Performance

Purpose Antibiotic resistance necessitates the development of alternative therapeutic agents, particularly those targeting biofilm formation. This study investigated the biosynthesis of silver nanoparticles (AgNPs) using Stenochlaena palustris (Kelakai) leaf extract and their formulation into a carbopol-based hydrogel system. Method Phytochemical identification of Kelakai ( Stenochlaena palustris ) leaf extract was conducted using thin-layer chromatography (TLC) with specific reagents to detect secondary metabolites such as flavonoids, phenols, tannins, steroids, terpenoids, saponins, and alkaloids. Silver nanoparticles (AgNPs) were biosynthesized by reacting the extract with 1 mM AgNO₃, and nanoparticle formation was indicated by a gradual color change of the solution over 24 hours. Particle size, polydispersity index, and surface charge were conducted using particle size analyzer and zeta potential. Morphological characterization using scanning electron microscopy (SEM) and transmission electron microscopy (TEM).The biosynthesized AgNPs were incorporated into a Carbopol 940 hydrogel and evaluated for stability, antibacterial activity against Staphylococcus aureus and Escherichia coli , and antibiofilm activity during both the attachment prevention and mature biofilm disruption stages. Result The extract served as a bioreducing agent to produce AgNPs, which were characterized as spherical structures with an average size of 101.1 nm. The synthesized nanoparticles were incorporated into hydrogels at varying concentrations and evaluated for physical stability, viscosity, spreadability, and adhesiveness. All formulations exhibited excellent physical stability following six freeze–thaw cycles. In antibacterial evaluations against Staphylococcus aureus and Escherichia coli using the disk diffusion method, the AgNP hydrogels produced significantly larger inhibition zones than their extract, with the highest concentration formulation exhibiting the most potent activity. Furthermore, antibiofilm assays demonstrated that the hydrogels significantly inhibited both the attachment and destruction phases of biofilm development compared to controls. Conclusion These findings suggest that AgNP-loaded hydrogels containing Stenochlaena palustris extract significantly enhance antimicrobial efficacy, with promising potential as topical formulations for managing bacterial infections and biofilm-associated conditions.