Hydrophilic PAAm/SA-Ca2+ Hydrogel Coating for Ureteral Stents With Lubrication, Antimicrobial Adhesion, and Anti-Stone Functions

Conventional ureteral stents frequently cause mucosal damage during placement due to surface hydrophobicity and elevated friction coefficients. Additionally, post-insertion complications such as bacterial adhesion and calculus deposition pose significant clinical risks. To address these challenges, we developed a polyacrylamide/sodium alginate-Ca 2+ (PAAm/SA-Ca 2+ ) dual-network hydrogel as a functional coating for ureteral stents. By modulating calcium chloride (CaCl 2 ) concentration, we optimized the PAAm/SA-Ca 2+ dual-network hydrogel's cross-linking density, resulting in enhanced hydrophilicity, reduced swelling ratio (from 48.5% to 17.3%), and a lower coefficient of friction (COF) (from 0.19 to 0.06). The hydrogel coating exhibited excellent stability and sustained lubricity with a uniform thickness of approximately 16 μm. Notably, the coating reduced calculus deposition by 74% over a 7-day period and demonstrated exceptional antibacterial efficacy, achieving 97% inhibition against Escherichia coli ( E. coli ) and 98% against Staphylococcus aureus ( S. aureus ). Furthermore, the coating displayed favorable hemocompatibility. These findings highlight the potential of PAAm/SA-Ca 2+ dual-network hydrogel coatings for improving ureteral stent performance.