Green chemistry fabrication of durable antimicrobial peptide-immobilized silk fibroin films for accelerated full-thickness wound healing

Silk fibroin (SF) has been intensively explored for wound dressings due to its excellent biological and mechanical properties. However, forming SF films with a combination of durable and excellent antibacterial properties as well as biocompatibility is still a challenge. Herein, a marine-derived antimicrobial peptide, actinomycin X2 (Ac.X2), was immobilized onto SF fibers and Ac. X2-immobilized SF (ASF) films was further prepared using all green chemical approaches. The immobilized amount of Ac. X2 can be precisely quantified by its characteristic UV–visible absorption peak at 443 nm. Both Fourier transform infrared spectroscopy (FTIR) and solid-state 13C NMR spectra revealed that the lactone bond on the α/β rings of Ac. X2 was covalently grafted with the amino groups of SF, which greatly improved the degree of immobilization. The ASF film exhibited excellent antimicrobial activity against Staphylococcus aureus and Methicillin-resistant S. aureus (MRSA), with no biofilm formation. Furthermore, the ASF film showed a suitable degradation rate, good hemocompatibility, and reduced cytotoxicity in vitro biocompatibility assay. In vivo rat full-thickness wound healing experiment, the ASF film exhibited effectively promote skin regeneration, wound vascularization, and restore skin function compared with the control and SF wound dressings. These results suggest that the versatile ASF film would be a potential wound dressing for clinical application.