Robust and durable zwitterionic hydrogel coating with catechol-Cu²⁺ coordination for antithrombotic and antibacterial...

Thrombosis and bacterial infection remain two major life-threatening complications associated with blood-contacting medical devices. Although zwitterionic hydrogel coatings mitigate these risks by forming strongly hydrated interfaces that resist protein, platelet, and bacterial adhesion, their clinical translation is often limited by excessive swelling, weak interfacial adhesion, and insufficient long-term biofunctionality. Herein, we report a mechanically robust zwitterionic hydrogel coating reinforced by a hybrid network integrating covalent crosslinks, catechol-Cu²⁺ coordination, and electrostatic interactions, enabling durable antithrombotic and antibacterial performance. The coating was fabricated via a simple dip-coating process followed by photo-crosslinking, forming a uniform and stable hydrogel layer on thermoplastic polyurethane substrates. This hybrid architecture provides strong interfacial adhesion, enhanced wear resistance, and high tensile strength and extensibility. The hydrated zwitterionic interface significantly reduces friction and effectively suppresses the adsorption of proteins with different charges, as well as the adhesion of mammalian cells, red blood cells, platelets, and bacteria. Meanwhile, incorporated Cu²⁺ catalyzes sustained nitric oxide generation to actively inhibit platelet activation and thrombus formation, while also exerting broad-spectrum antibacterial activity against S. aureus and E. coli. The coating demonstrates effective catheter patency maintenance and pronounced thromboresistance in an extracorporeal rabbit circulation model. Long-term immersion studies further confirm sustained antifouling, antibacterial, and anticoagulant performance, attributed to high Cu²⁺ retention within the hybrid network. Overall, this work presents a mechanically reinforced and durable zwitterionic hydrogel coating strategy that integrates passive antifouling with active nitric oxide-mediated regulation, offering a promising surface-engineering platform for blood-contacting medical devices.