A recombinant humanized type III collagen coating with anti-inflammatory and endothelialization-promoting effects for...

Transcatheter cardiac occluders represent a mainstay of minimally invasive therapy for congenital heart disease and for the prevention of left atrial appendage-related thrombosis. However, their long-term clinical efficacy is constrained by frequent post-implant complications, including device-related thrombosis, persistent inflammation, incomplete reendothelialization, and delayed tissue healing. Herein, we developed a hierarchical functional modification strategy for biodegradable polymers via stable covalent grafting of recombinant humanized type III collagen (rhCol III)-a biomaterial with robust cell adhesiveness and low immunogenicity-onto the polymer surface. Systematic in vitro assays demonstrated that the rhCol III coating effectively inhibited coagulation, enhanced endothelial and cardiomyocyte function, and modulated inflammation through promoting the polarization of macrophages to the anti-inflammatory M2 phenotype. In vivo, this innovative coating achieved 71.68% endothelialization at 40 days post-implantation, nearly double that of unmodified controls, and transcriptomic analysis further validated its acceleration of reendothelialization and tissue healing. Collectively, this multifunctional rhCol III coating integrates anticoagulant, anti-inflammatory and pro-endothelialization properties, providing a promising translational strategy to advance left atrial appendage occluders from passive mechanical occlusion to active biofunctional regeneration.