Anti-fouling plus: Engineered stent coating with inflammation-regulation capability enables enhanced tissue healing

Coagulation, inflammation, and hyperplasia frequently restrict the effectiveness of cardiovascular stents. It is critical to modify stent surfaces to allow for in situ tissue healing. Interrelated coagulation and inflammation can impede endothelialization and are critical to the long-term performance of cardiovascular implants. This study proposes a relatively bio-inert "Anti-fouling plus" coating that is effective in anti-coagulation and anti-inflammation at the early stage of implantation and provides mild inflammatory responses during tissue remodeling process. The phosphorylcholine (PC)-based polymer PM(PCLA) is reacted onto a polydopamine-treated polylactic acid (PLA) surface. PC-based polymers that mimic cell membranes present remarkable antiinflammation and anticoagulation properties. The composite of epigallocatechin gallate (EGCG) and tempol is loaded on the PM(PCLA) coating to achieve "anti-fouling plus" which can mediate inflammatory responses by scavenging reactive oxygen species. In vitro hemocompatibility and cell tests demonstrate the effectiveness of coatings in inhibiting thrombus and inflammation. Interestingly, this study originally reveals a novel strategy that the anti-fouling plus coating can direct vascular tissue healing on stent via promoted endothelialization and mediated contractile smooth muscle cell phenotype by switching inflammatory cells to a pro-repair phenotype during tissue healing process, even if the coating is relatively bio-inert.