In vitro and in vivo investigational studies of a nanocomposite-hydrogel-based dressing with a silver-coated chitosan wafer for full-thickness skin wounds

A nanocomposite reservoir-type hydrogel dressing of poly vinyl alcohol (PVA) was fabricated by a freeze-thaw method and loaded with silver-nanoparticle-coated chitosan wafers (Ag-CHWs). The Ag-CHWs were synthesized by a sonication technique with silver nitrate (AgNO3) and chitosan powder. Scanning electron microscopy images showed silver nanoparticles (AgNPs) with a size range of 10 +/- 4nm on the surface of the chitosan wafers, and the antibacterial efficacy (minimum inhibitory concentration) of the Ag-CHWs was measured against Pseudomonas aeruginosa (32 mu g/mL), Staphylococcus aureus, (30 mu g/mL) and Escherichia coli (32 mu g/mL). The antimicrobial PVA hydrogel showed an improved tensile strength (approximate to 0.28 MPa) and gel content (approximate to 92%) in comparison with the blank hydrogels. Full-thickness-excision wound studies of the nanocomposite dressing on Wistar rats revealed enhanced wound contraction, improved inflammation response, re-epithelization rate, neoangiogenesis, and granulation tissue formation in comparison to the control group. A flexible, biocompatible, nanocomposite reservoir dressing not only established the chitosan as a stabilizer but also proved the efficacious and safe utility of AgNPs toward chronic wound management. (c) 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43472.