Carrageenan-based functional hydrogel film reinforced with sulfur nanoparticles and grapefruit seed extract for wound healing application.

κ-Carrageenan-based (Carr) functional wound healing hydrogel films were prepared by incorporating chitosan capped sulfur nanoparticles (SNP) and grapefruit seed extract (GSE). In vivo wound healing effect of the hydrogel films was tested using artificially wounded male Sprague-Dawley rats. The hydrogel film (Carr/GSE/SNP) showed higher mechanical strength, swelling ratio and ultraviolet barrier properties than the carrageenan film, but the water vapor permeability and water solubility were decreased. The hydrogel film showed antibacterial activity strong enough to destroy Staphylococcus epidermis and Escherichia coli within 3 h of incubation and showed high biocompatibility against mouse fibroblast (L929 cell lines). The hydrogel film (Carr/GSE/SNP3%) showed excellent wound healing effect (1.3% wound area after 2 weeks) compared to the control group (31% wound area after 2 weeks) through in vivo wound healing test. Histological examination showed the complete appearance of the healed epidermis. The Carr/GSE/SNP hydrogel films are most likely to be used for the treatment of full-thickness wounds.