Functionalized biomimetic smart suture with composite coating combined with transcutaneous electrical stimulation for tendon - skin repair.

Abstract

Sutures serve as the primary material in tendon repair surgery, utilized for the dual purpose of suturing both tendons and skin. However, existing sutures and their modified versions are limited by mechanical mismatch with tissues and a lack of advanced functionalities, rendering them unable to actively participate in tissue healing and regeneration. Inspired by the synergistic interface between tendons and their sheaths, we developed an intelligent suture system (SHTP@bFGF) by integrating a composite coating onto the suture substrate through hierarchical interface assembly of thiolated chitosan microgel loaded with bFGF and conductive PPy. The structure achieves mechanical compliance matching through covalent cross-linking between the microgel network and suture substrate; enables electrophysiological signal modulation via continuous electronic pathways constructed with PPy; establishes synergistic antibacterial defense by leveraging the hydrophilicity of the composite coating to reduce protein adsorption while employing electrostatic interactions for bactericidal action; and significantly enhances bFGF bioavailability through pH/GSH dual-triggered stimulus-responsive drug delivery. In rat models of Achilles tendon rupture and full-thickness skin injury, the SHTP@bFGF sutures, in combination with transcutaneous LVMAS therapy, demonstrated significant regenerative effects. This hierarchical design strategy, which integrates fibrous scaffolds with hydrogel interfaces and functional coatings, provides a transformative paradigm for developing active medical textiles. STATEMENT OF SIGNIFICANCE: The SHTP@bFGF smart suturing system achieves electrophysiological conduction, pH/GSH-responsive drug delivery, and antibacterial protection through a composite coating. Its modular design ensures broad compatibility with various commercial sutures and fibrous substrates. When combined with transcutaneous low-voltage microamperage stimulation, the system demonstrates exceptional dual-repair capabilities, significantly accelerating healing in Achilles tendon rupture and full-thickness skin injury models. This multifunctional approach not only addresses mechanical mismatches but also actively promotes tissue regeneration, offering a transformative solution for complex tendon-skin repair while reducing postoperative infection risks. Its versatility and efficacy make it a highly promising candidate for advanced wound management and regenerative medicine.