Starch-mediated synthesis of chitosan/silver nanocomposites for antibacterial, antibiofilm and wound healing applications

Chitosan(CS)/silver(Ag) nanocomposites (NCs) were obtained using Ag nanoparticles (NPs) synthesised via starch-mediation, which were subsequently decorated with CS. Sphere-shaped NPs and NCs with average diameter sizes of ∼20 nm for Ag NPs and ∼21 nm for CS/Ag NCs were obtained. Ag NPs and CS/Ag NCs exhibited antibacterial activity against Pseudomonas aeruginosa, Escherichia coli, multi-drug resistant Klebsiella pneumoniae and Salmonella typhi with minimum inhibition concentrations values ranging from 1.3 to 7.8 μg mL−1. CS/Ag NCs possessed higher biofilm inhibition activity against P. aeruginosa and K. pneumoniae than Ag NPs. NBT assay results confirmed the ROS-mediated antibacterial activity of Ag NPs and CS/Ag NCs. Ag NPs and CS/Ag NCs were evaluated for their hemolytic activity with values of 12 and 13%, respectively, suggesting their relative hemocompatibility. Also, the NCs were found to be more cyto-compatible to L929 mouse fibroblast cells compared to Ag NPs. Finally, CS/Ag NCs were found to promote cell migration by wound gap closure of L929 mouse fibroblast cells. The study suggested that CS/Ag NCs could be potentially used as safe, suitable wound healing agents to treat drug resistant biofilm-forming bacterial wound infections and simultaneously favoring the wound healing process.