Zwitterionic Coatings for Urinary Catheters: Current Progress, Design Principles and Translational Challenges

Catheter-associated urinary tract infection (CAUTI) is one of the most common healthcare-associated infections and remains a major cause of morbidity, catheter blockage, and repeated device replacement during long-term catheterization. This narrative review examines the interfacial processes that contribute to urinary catheter failure, including protein adsorption, microbial adhesion, biofilm formation, encrustation, and swarming-associated blockage, and evaluates how zwitterionic surface coatings may address these challenges. Drawing primarily on urinary catheter-specific studies, together with adjacent zwitterionic biomaterials literature where relevant to catheter design, this review synthesizes current coating strategies with emphasis on protein repellence, lubrication, biocompatibility, multifunctionalization, interface-specific design requirements, architectural trade-offs between hydrogel-like and brush-like coatings, and approaches to improve coating durability. The review also considers translation, including interim human evidence for zwitterion-treated urinary catheters, while recognizing that these data remain conference-reported and product-specific. Overall, zwitterionic coatings should be viewed not as a single antifouling solution, but as a versatile biomaterials platform for engineering multifunctional, durable, and clinically translatable urinary catheters. However, their long-term stability, resistance to complex biofilm and encrustation processes, and clinical efficacy require further validation. To define these remaining validation needs, the review compares PC-, SB-, and CB-based systems, stratifies evidence by model and duration, reports quantitative coating data where available, and identifies validation requirements across the product lifecycle.