Lignin-mediated Green Synthesis of AgNPs in Carrageenan Matrix for Wound Dressing Applications

Carrageenan-based functional wound dressing materials were prepared through a one-pot green synthesis of silver nanoparticles (AgNPs) using lignin as a reducing and capping agent in the carrageenan matrix cross-linked with divalent cations such as CaCl₂, CuCl₂, and MgCl₂. The wound healing efficacy of the hydrogel film was evaluated using Sprague-Dawley rats. Crosslinking with divalent cations improved the physical properties of carrageenan-based hydrogels containing AgNPs such as strength, flexibility, swelling ratio, and release rate of Ag ions depending on the type of crosslinking agent used. The carrageenan-based hydrogels were biocompatible against the mouse fibroblast cell line (L929 cell line). Carra/Lig/AgNPs/MgCl₂ hydrogel significantly healed the wounds in Sprague-Dawley rats within two weeks, reducing the wound area to <3%, which was further confirmed by histological analysis with the epidermis and mature glands. Carrageenan-based multifunctional hydrogels have a high potential for wound dressing applications.

Keywords: Antibacterial activity; Carrageenan; Lignin; Nanocomposite hydrogels; Silver nanoparticles; Wound dressing.