Sulfated poly(aspartic acid) coatings as next-generation biomimetic interfaces for blood-contacting devices.

The increasing reliance on blood-contacting medical devices underscores the need for materials that minimise thrombosis and inflammation. Devices such as stents and dialysis membranes often face complications related to clot formation and microbial colonisation. To address these challenges, this study explored the development of sulfated poly(aspartic acid) (sPASP) coatings aimed at improving haemocompatibility and reducing infection risk. PASP, a biodegradable, biocompatible polymer, and calcium chelator, served as the base material, with sulfation introduced to enhance its antithrombotic, antibacterial, and anti-inflammatory properties. Sulfate groups mimic natural anticoagulants such as heparin, potentially promoting antithrombin activity and inhibiting clot development. The coatings were fabricated via a simplified one-pot process on polydopamine-modified substrates. The degree of sulfation was systematically varied from 10% to 80% to optimise the material's performance and thoroughly evaluated across multiple dimensions of blood compatibility. Assessments included surface physicochemical properties, protein adsorption, platelet adhesion, antithrombotic efficacy, cellular compatibility, and antibacterial activity, under static and dynamic conditions. Notably, sPASP with a sulfation degree of 40% exhibited the most favourable blood compatibility, demonstrating strong potential compared to heparin-mimicking polysaccharide coatings. In addition, the material exhibited excellent in vivo biocompatibility in implantation models, further underscoring its promise as a high-performance, multifunctional biomimetic interface for blood-contacting biomedical applications.