Multilayer Antibacterial Hydrogel Wound Dressings Incorporated With Green Synthesized Silver Nanoparticles

Multilayer antibacterial hydrogel wound dressings were fabricated and characterized for wound healing applications. Dressings are designed to achieve infection control, moisture management in the wound area and to support wound healing. Multilayer wound dressings were prepared as three layers by solvent casting method. The upper layer is composed of kappa carrageenan and green synthesized silver nanoparticles (AgNPs, similar to 122 nm in size, zeta potential of -35 mV) to provide the moist control, and to form a barrier against microorganism attack. Lidocaine HCl loaded polyvinyl alcohol and chitosan-based middle layer was designed to achieve controlled drug release and to add strength to the hydrogel structure. The lower layer is composed of hyaluronic acid and ovalbumin to serve a controlling membrane for controlled drug release, and to further support wound healing. Different amounts of AgNPs were used in formulations to evaluate their impact on multilayer wound dressings. The incorporation of AgNPs resulted in reduced swelling values and degradation rates of the multilayer wound dressings, enhanced mechanical capabilities, and no significant change in water vapor permeability values. They have demonstrated enhanced antibacterial efficacy against Klebsiella pneumoniae, Bacillus subtilis and Candida albicans. The optimal multilayered hydrogel, incorporating AgNPs and loaded with lidocaine HCl, has shown biocompatibility and hemocompatibility, exhibiting 60% degradation by day 14, water vapor permeability of 2022 +/- 460 g/m(2) over 24 h, a tensile strength of 6.71 +/- 0.62 MPa, 36.38% +/- 3.62% elongation at break, and 65.72% +/- 14.80% drug release within 10 h, making it a promising candidate for facilitating the wound healing process.