Antibacterial and wound healing-promoting effect of sponge-like chitosan-loaded silver nanoparticles biosynthesized by iturin.

Silver nanoparticles (AgNPs) are widely used in wound dressing, but are limited in the application due to its high toxicity at effective concentrations. iturin-AgNPs was previously found to have much higher antibacterial activity at lower AgNPs content than the commercial AgNPs. To verify its potential application in the promotion of wound healing, a chitosan (CS) composite sponge dressing-loaded iturin-AgNPs was developed and evaluated for their antibacterial activity in vitro and used for wound healing in vivo. As results, the synthesized CS dressing had high porosity and water absorption. As expected, the antibacterial activity of CS dressing was significantly promoted by the incorporation of iturin-AgNPs. The CS dressing-loaded iturin-AgNPs showed more effective inhibition of bacterial infection and promotion of wound healing processing and quality than the commercial wound dressing loaded AgNPs in vivo. The mechanisms for the promotion of wound healing by the CS dressing-loaded iturin-AgNPs were found as the enhancement of re-epithelialization and collagen formation, as well as the increased antibacerial activity. No toxicity was found to all organs of mice. The study developed an efficient way to enhance the antibacterial activity of CS dressing loaded AgNPs at low toxicity, which has great potential in wound care application.