Silver Nanoparticles-Loaded Poly(Vinyl Alcohol)/Chitosan/Graphene Hydrogels Obtained by Electrochemical Synthesis

Abstract

Recent advances in biomaterials science are increasingly focused on (re)search for next-generation soft tissue regeneration solutions. Hydrogel-based materials are becoming a focal point to address many tissue engineering requirements, possessing exceptional biocompatibility, with tailorable shape, structure and mechanical properties, as well as infinite possibilities drug delivery. The widespread antibiotics use has led to aggravated resistance issues in many bacterial strains, so the focus is increasingly shifted towards alternative antibacterial solutions such as silver nanoparticles (AgNPs). In this work, we have developed novel composite materials based on poly(vinyl alcohol)/chitosan (PVA/CHI) and poly(vinyl alcohol)/ chitosan/graphene (PVA/CHI/Gr) hydrogels with silver nanoparticles obtained through green in situ constant-voltage electrochemical synthesis. The obtained AgNPs’ properties, sizes and size distributions were examined using UV-visible spectroscopy, dynamic light scattering and transmission electron microscopy. In vitro swelling and silver release kinetics were monitored in the simulated physiological conditions (pH7.4, 37 C). The obtained release and swelling isotherms were fitted with several theoretical models that helped discern the mechanisms of these processes. Tensile testing was carried out to examine the composites’ mechanical behavior and elasticity – important properties for soft tissue engineering materials. Finally, the excellent antibacterial activity of the obtained silver/ poly(vinyl alcohol)/chitosan (Ag/PVA/CHI) and silver/poly(vinyl alcohol)/chitosan/graphene (Ag/PVA/CHI/Gr) hydrogels against Staphylococcus aureus and Escherichia coli was confirmed quantitatively by colony counting method, and their non-toxicity was verified towards two model fibroblast cell lines (MRC-5 and L929) utilizing the MTT assay. Through thorough characterization, the obtained nanocomposite hydrogel materials were identified as strong candidates for active antibacterial soft tissue engineering materials.