Carboxybetaine zwitterionic coatings on kidney dialyzer components: Surface characterization and blood interactions

Chronic Kidney Disease (CKD) affects a significant portion of the population, leading to end-stage renal disease (ESRD). ESRD is most often addressed by hemodialysis treatment, however, clinically significant interactions can occur between blood components, the dialysis membranes and the entire dialysis circuit. Zwitterionic compounds, such as polycarboxybetaine (PCB), are known for their ability to prevent blood protein adsorption and reduce platelet and complement activation. We synthesized and characterized two carboxybetaine (CB)-based copolymers tailored for coating the tubing and dialyzer components of the extracorporeal circuit. Utilizing both UV irradiation immobilization and a hydrophobic self-attachment technique, we successfully coated the tubing and dialyzer surfaces, respectively, with these zwitterionic copolymers. In vitro testing involved subjecting freshly drawn whole human blood through both, coated and uncoated circuits, under simulated hemodialysis circuit conditions. After one hour of continuous blood circulation and circuit contact, we assessed platelet and complement activation levels. Our results demonstrate significantly reduced platelet and complement activation and protein fouling on the zwitterionic-coated circuits compared to uncoated counterparts, indicating improved blood compatibility. This research underscores the potential of zwitterionic coatings as a promising approach to mitigate the need for continuous anticoagulation in hemodialysis treatment. By enhancing the blood compatibility of extracorporeal circuits, these coatings offer a safer and more effective solution for patients with ESRD undergoing hemodialysis. STATEMENT OF SIGNIFICANCE: Our research addresses a critical challenge in hemodialysis treatment, where the existing extracorporeal circuits often require continuous anticoagulation due to poor blood compatibility, leading to risks and complications for patients. By exploring the application of zwitterionic coatings, specifically polycarboxybetaine (PCB)-based materials, we offer a promising solution to enhance blood compatibility. Through the synthesis and characterization of two tailored carboxybetaine (CB)-based copolymers, we successfully coated tubing and dialyzer surfaces, significantly reducing platelet and complement activation in in vitro testing compared to uncoated circuits. These findings underscore the potential of zwitterionic coatings to improve the safety and effectiveness of hemodialysis treatment, paving the way for further research and potential clinical applications.