Silver nanoparticle loaded collagen/chitosan scaffolds promote wound healing via regulating fibroblast migration and macrophage activation

TLDR

Full‑thickness skin defects pose infection risks and scarring, and although silver nanoparticles are promising antimicrobials for burn wounds, their detailed mechanism remains unknown. The study constructed a metallic nanosilver‑collagen/chitosan hybrid scaffold (NAg‑CCS) to evaluate its effects on wound healing. The scaffold’s antibacterial activity, in vitro fibroblast migration assays, and in vivo therapeutic effects in full‑thickness skin defects in Sprague‑Dawley rats were assessed. In vitro, 10 ppm NAg accelerated fibroblast migration and α‑SMA expression; in vivo, NAg‑CCS increased pro‑inflammatory, scar‑related, and macrophage activation markers, and by day 60 regenerated skin resembled normal skin, demonstrating bactericidal, anti‑inflammatory, and wound‑healing properties that make it an ideal dermal substitute.

Abstract

Treatment of full-thickness skin defects poses significant clinical challenges including risk of infection and severe scaring. Silver nanoparticle (NAg), an effective antimicrobial agent, has provided a promising therapeutic method for burn wounds. However, the detailed mechanism remains unknown. Hence, we constructed a metallic nanosilver particles-collagen/chitosan hybrid scaffold (NAg-CCS) and investigated its potential effects on wound healing. In vitro scratch assay, immunofluorescence staining and antibacterial activity of the scaffold were all studied. In vivo NAg-CCS was applied in full-thickness skin defects in Sprague-Dawley (SD) rats and the therapeutic effects of treatment were evaluated. The results showed that NAg at a concentration of 10 ppm accelerated the migration of fibroblasts with an increase in expression of α-smooth muscle actin (α-SMA). Furthermore, in vivo studies showed increased levels of pro-inflammatory and scar-related factors as well as α-SMA, while markers for macrophage activation were up-regulated. On day 60 post transplantation of ultra-thin skin graft, the regenerated skin by NAg-CCS had a similar structure to normal skin. In summary, we demonstrated that NAg-CCS was bactericidal, anti-inflammatory and promoted wound healing potentially by regulating fibroblast migration and macrophage activation, making it an ideal dermal substitute for wound regeneration.