Starch based sulfobetaine zwitterionic coatings for anticoagulation

Blood-contacting medical devices often suffer from thrombosis and bacterial infections. While zwitterionic polymers exhibit excellent antifouling properties, their conventional syntheses require complex routes and toxic metal catalysts. Herein, we present a metal-catalyst-free strategy for fabricating a renewable starch-based sulfobetaine zwitterionic coating (OSt-SBSi), in which zwitterionic antifouling groups and hydrolyzable silane groups are incorporated into the same polymer backbone. Crucially, the coating is stably immobilized on substrates through multi-site siloxane-based covalent anchoring, overcoming the delamination issues of physical adsorption. Concurrently, zwitterionic moieties and the starch backbone synergistically form a tightly bound hydration layer. This robust barrier imparts broad-spectrum biofouling resistance, drastically reducing the adhesion of proteins, cells, platelets, and pathogenic bacteria. Consequently, the OSt-SBSi coating demonstrates excellent hemocompatibility and effectively prevents thrombus formation in a dynamic ex vivo blood circulation model, maintaining anticoagulant activity and structural integrity even after 7 days of aqueous immersion. This scalable, eco-friendly strategy offers a promising approach for the development of next-generation blood-contacting biomedical devices.