Mechanically robust zwitterionic hydrogel coating reinforced by microgels for antibacterial and anticoagulant applications.

Nosocomial infections and thrombosis associated with implantable medical devices have emerged as increasingly critical clinical challenges. Antifouling hydrogels, owing to their biocompatibility and highly hydrophilic surfaces, have garnered significant attention as a promising strategy to mitigate these complications. However, conventional hydrogels often suffer from poor mechanical strength due to their high-water content and the absence of efficient energy dissipation mechanisms, leading to weak adhesion to underlying substrates and potential detachment under physiological conditions. In this study, vinyl-functionalized poly(N-isopropylacrylamide-co-acrylic acid) microgels were incorporated into polysulfobetaine hydrogel networks to overcome these limitations. The microgels enhanced the crosslinking density to improve the mechanical strength of the hydrogels, acted as sacrificial bonds for energy dissipation, and functioned as carriers for antibacterial agents. The polysulfobetaine hydrogel coating effectively reduced the friction coefficient and significantly improved antibacterial and anti-platelet adhesion performance. Moreover, antimicrobial-loaded microgels imparted the hydrogel coating with enhanced antibacterial functionality. The in vivo anticoagulant performance of the hydrogel-coated catheter was validated through implantation into the external jugular vein of rabbits, confirming its therapeutic potential. This multifunctional hydrogel coating strategy presents a promising avenue for the development of mechanically robust, antibacterial, and anticoagulant surface modifications for implantable biomedical devices.