A dynamic remodeling bio-mimic extracellular matrix to reduce thrombotic and inflammatory complications of vascular implants.

Thrombotic and inflammatory complications induced by vascular implants remain a challenge to treat cardiovascular disease due to the lack of self-adaption and functional integrity of implants. Inspired by the dynamic remodeling of the extracellular matrix (ECM), we constructed a bio-mimic ECM with a dual-layer nano-architecture on the implant surface to render the surface adaptive to inflammatory stimuli and remodelable possessing long-term anti-inflammatory and anti-thrombotic capability. The inner layer consists of PCL-PEG-PCL [triblock copolymer of polyethylene glycol and poly(ε-caprolactone)]/Au-heparin electrospun fibers encapsulated with indomethacin while the outer layer is composed of polyvinyl alcohol (PVA) and ROS-responsive poly(2-(4-((2,6-dimethoxy-4-methylphenoxy)methyl)phenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane) (PBA) fibers. In response to acute inflammation after vascular injury, the outer layer reduces ROS rapidly by PBA degradation for inflammation suppression. The degraded outer layer facilitates inner layer reconstruction with enhanced hemocompatibility through the H-bond between PVA and PCL-PEG-PCL. Furthermore, chronic inflammation is effectively depressed with the sustained release of indomethacin from the inner layer. The substantial enhancement of the functional integrity of implants and reduction of thrombotic and inflammatory complications with the self-adaptive ECM are demonstrated both in vitro and in vivo. Our work paves a new way to develop long-term anti-thrombotic and anti-inflammatory implants with self-adaption and self-regulation properties.