Zwitterionic Topological Hydrogel Coatings for Robust Mitigation of the Foreign Body Response.

Implantable medical devices are prone to foreign body response (FBR) during long-term use. Zwitterionic materials have attracted significant attention for their excellent antifouling properties and have been applied to implantable devices to enhance immunocompatibility. However, in vivo studies have yielded inconsistent results regarding their effectiveness as anti-FBR surface coatings. In this study, three types of zwitterionic poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) coatings, including PMB30 copolymers, polymer brushes constructed via ATRP (atom transfer radical polymerization), and topological hydrogel coatings (THC), are comparatively evaluated for their anti-FBR efficacy. The results show that THC coatings, characterized by highly entangled polymer networks and thick hydration layers, exhibit the strongest anti-FBR performance compared to other structural forms. This coating effectively reduces fibrous capsule formation on polydimethylsiloxane (PDMS) substrates with varying roughness and stiffness, and also in silicone breast implants, highlighting its translational potential for clinical applications. Overall, this work provides a comparative evaluation of representative PMPC coating strategies and identifies THC coatings as a promising approach for improving the immunocompatibility of implantable devices.