Evaluation of Dual Effect of Sodium Borohydride (NaBH4) as a Reducing and Crosslinking Agent for Development of Novel Silver Nanoparticles (AgNPs) Loaded Chitosan-Poly (Vinyl Alcohol) (CS-PVA) Hydrogels for Wound Healing Activity

Purpose: Hydrogels are three-dimensional, crosslinked polymeric systems with high hydrophilicity and biocompatibility, making them ideal materials for wound healing applications. In this study, a silver nanoparticle (AgNP)-loaded chitosan–poly (vinyl alcohol) (CS–PVA) hydrogel was developed using a novel, simple, and cost-effective approach. In this approach, sodium borohydride (NaBH₄) simultaneously acts as a reducing agent for AgNP synthesis and as a physical crosslinking agent for hydrogel formation. Methods: AgNPs were synthesized via NaBH₄-mediated reduction and characterized by dynamic light scattering and UV–Vis spectroscopy. The resulting hydrogels were evaluated by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy-dispersive X-ray (EDS) spectroscopy, swelling, porosity and mechanical test. In vitro biocompatibility and wound healing potential were assessed using cell viability assays and a scratch wound assay. Results: Among all formulations, M30, an AgNP-loaded CS–PVA hydrogel, prepared with medium molecular weight (MMW) chitosan and 30 mL of AgNP suspension, had the best overall performance with the highest swelling degree, favorable mechanical performance. It maintained cell viability above 80% at 24 and 48 h, and showed the greatest wound closure rate, even at low AgNP concentration. Conclusion: The results demonstrate that AgNP-loaded CS–PVA hydrogels prepared using NaBH₄ as a dual-function agent exhibit promising biocompatibility and wound healing potential even at low AgNP content. To the best of our knowledge, this study is the first to demonstrate the dual functionality of NaBH₄ in a single-step approach as both a reducing and physical crosslinking agent, providing a simple and promising strategy for the development of next-generation wound dressing materials without need for additional chemical crosslinkers.