Electroactive and antibacterial surgical sutures based on chitosan-gelatin/tannic acid/polypyrrole composite coating

Surgical sutures pervade almost all surgeries; however, their clinical therapy effects are barely satisfactory due to the lack of physiological signal responsiveness and the prone surgical site infection (SSI). Herein, the functional sutures (PCGT@S) with electroactivity and antibacterial properties were fabricated by decorating the suture surfaces with chitosan-gelatin/tannic acid/polypyrrole (CS-GE/TA/PPy) composite coating . Thanks to the assistance of CS-GE/TA on the polymerization of PPy, the inherent brittleness of PPy was alleviated and ensured PCGT@S excellent conductivity even under knotted state, thereby providing stable physiological electrical signal transmission among cells and regulating cell behaviors actively. Meanwhile, the synergistic effects of CS-GE/TA and PPy offered PCGT@S outstanding antibacterial rates of over 99% against E. coli and S. aureus without involving any additional drugs. Furthermore, in vivo studies revealed that PCGT@S could enhance wound healing dramatically, as evidenced by less inflammatory reaction, better angiogenesis, cell proliferation , re-epithelization, granulation tissue, and collagen regeneration. This study successfully demonstrates the feasibility of the electroactive and antibacterial sutures for promoting tissue regeneration and provides a new idea for exploring the next generation bioactive suture.