A polyzwitterion-based antifouling and flexible bilayer hydrogel coating

A coating of implanted medical devices with antifouling ability, preferable mechanical property and stability in the physiological environment proves beneficial for their clinical use. Here we develop a flexible bilayer hydrogel coating with self-healing, antifouling, and lubricating functions. Our bilayer coating consists of two functional layers: i) an adhesive flexible polyelectrolyte hydrogel layer, ii) an antifouling and lubricous polyzwitterionic layer. The bilayer hydrogel coating is prepared in two steps dip-coating and in situ UV photopolymerization . Our results demonstrate that the prepared bilayer hydrogel coating has proper mechanical properties , favorable hydrophilicity , and lower surface friction . We demonstrate that the bilayer hydrogel coating maintains hydrophilicity under extreme condition (1 h sonicating or 5000 times repeating bending). The as-prepared bilayer hydrogel coating resists non-specific protein adsorption , inhibits cell and platelet adhesion, and prevents thrombosis. This work provides a reliable coating on the medical materials, showing a promising practical application in diversified implantable medical devices .