Advanced Electroactive and Anti-Inflammatory Sutures for Enhancing Tendon and Bone Regeneration to Promote Repair of Achilles Tendon Sleeve Avulsion

Achilles tendon sleeve avulsions often involve tissue defects. Standard bone tunnel fixation risks tunnel enlargement, inflammation, and graft failure. Native tendon and bone tissue exhibit inherent bioelectrical properties whose disruption impedes healing. To address these, the study developed electroactive, anti-inflammatory sutures featuring a strong polylactic acid (PLA) micron yarn core and a conductive poly(3,4-ethylenedioxythiophene)/hydroxyethyl cellulose/glycerol/chondroitin sulfate/PLA (PEDOT/HEC/glycerol/CS/PLA) nanofibrous shell. A novel synthesis strategy enabled EDOT polymerization templated by HEC, eliminating the need for poly(styrene sulfonate) (PSS), oxidants, or catalysts and allowing direct electrospinning. In vitro, it can regulate macrophage polarization and enhance tenocytes and bone marrow mesenchymal stem cell (BMSCs) proliferation and differentiation. In a rabbit Achilles tendon avulsion model, the suture enables secure tendon-to-bone fixation via calcaneal bone tunnels. At 12 weeks post-operation, the suture exerts anti-inflammatory effects by modulating CD206/CD86 expression. Electroactive suture significantly enhances tendon regeneration and bone formation within the tunnels, and achieves robust tendon-to-bone integration at the interface, markedly improving fixation stability. In summary, this electroactive, anti-inflammatory suture effectively promotes tendon-bone regeneration for repairing Achilles tendon sleeve avulsions.