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

Abstract

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 (AgNO 3 ) and chitosan powder. Scanning electron microscopy images showed silver nanoparticles (AgNPs) with a size range of 10 6 4 nm on the surface of the chitosan wafers, and the antibacterial efficacy (minimum inhibitory concentration) of the Ag-CHWs was measured against Pseudomonas aeruginosa (32 mg/mL), Staphylococcus aureus, (30 mg/mL) and Escherichia coli (32 mg/mL). The antimicrobial PVA hydrogel showed an improved tensile strength ($0.28 MPa) and gel content ($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. V C 2016 Wiley Periodicals, Inc. J.Appl. Polym. Sci. 2016, 133, 43472.

Antibacterial Hydrogels

“…Ag NP‐coated CS wafer‐loaded PVA hydrogels (PVA/Ag–CHW hydrogels) were formulated by a sonication technique and then used as a wound dressing. The PVA/Ag–CHW hydrogels improved the re‐epithelialization, increased angiogenesis, and enhanced wound healing without any undesirable inflammatory response . A thermoplastic hydrogel was synthesized from multiblock PEG–POSS (POSS; poly(hedral oligosilsesquioxane)) polyurethanes by Wu et al Without Ag, the hydrogel exhibited the most rapid and extensive biofilm formation.…”

Treatment Strategies for Infected Wounds

“…A large number of studies are now focused on formulations of wound dressings made from chitosan hydrogels that incorporate and release nano-Ag and Ag NPs [ 161 , 162 , 163 , 164 , 165 ]. For example, spherical Ag NPs of (10–30) nm were embedded into surfaces of nano-fibers for wound healing applications.…”

Antibiotic Delivery Strategies to Treat Skin Infections When Innate Antimicrobial Defense Fails

“…For optimal healing, chronic wounds and burns need to stay moist during the treatment and healing process, as this results in faster epithelialization and enhanced angiogenesis and collagen synthesis than a dry environment [64,65]. Additionally, a moist wound environment allows faster breakdown of dead tissue and fibrin, resulting in less scarring [66,67]. Finally, perhaps counterintuitively, maintenance of wound moisture has been observed to correlate to a significantly lower infection rate than keeping the wound site dry [68].…”