Functionalized PVA-silk blended nanofibrous mats promote diabetic wound healing via regulation of extracellular matrix and tissue remodelling

Chronic cutaneous ulcers, a complex pathophysiological diabetic condition, represent a critical clinical challenge in the current diabetes mellitus pandemic. Consequently, there is a compelling need for bioactive dressings that can trigger healing processes for complete wound repair. Silk fibroin (SF), a natural protein polymer from mulberry and non-mulberry silkworms, has properties that support accelerated wound healing rate. SF from non-mulberry variety possesses additional cell-binding motifs (arginine, glycine, and aspartate), offering cell-material interactions. This study is aimed to investigate wound healing efficacy of dressings made up of various SF varieties blended with poly(vinyl alcohol) biopolymer in alloxan-induced diabetic rabbit model. The nanofibrous mats have been developed using electrospinning and functionalized with growth factors and LL-37 antimicrobial peptide for sustained delivery. Following post 14-day treatment, non-mulberry SF (NMSF)-based dressings healed the wounds faster, in comparison with their mulberry Bombyx mori SF, poly(vinyl alcohol), and control counterparts (p<.01). NMSF-based dressings also supported faster granulation tissue development, angiogenesis, and reepithelialization of wounds. Gene expression study of matrix metalloproteinases and collagen proteins affirmed higher extent of tissue remodelling during the repair process. Furthermore, there was organized extracellular matrix deposition (collagen type I, collagen type III, elastin, and reticulin) and higher wound breaking strength in NMSF compared with other groups after 4weeks. These results validated the potential of NMSF-based bioactive dressings to regulate extracellular matrix deposition leading to faster and complete repair of chronic diabetic cutaneous wounds.