Zwitterionic multifunctional coatings with strong hydration for ureteral stents to inhibit infectious encrustation

In the complex urinary environment, an effective method is needed to combat ureteral stent encrustation. Herein, recognizing that the adsorption of mineral salts is the initial step in the encrustation process, we utilized the barrier effect of hydration layers to inhibit encrustation. Through molecular dynamics simulations, sulfobetaine methacrylate can form a hydration layer, which repels encrustation ions in a simulated urinary environment, preventing attachment. Then, we developed a multifunctional zwitterionic polymer coating on the polyurethane stent (PU/ATS) by employing UV-initiated free radical polymerization combined with a dip-coating technique. The hydration layer endows the coating with superhydrophilicity and excellent lubricity, effectively resisting 96.1 % and 83.5 % of encrustation in 30 days and 90 days of urine flow simulation and significantly reducing the bacteria adhesion. PU/ATS demonstrated improved anti-encrustation and anti-biofilm performance under infected conditions compared to the Bard® InLay Optima® stent. Moreover, in the rat bladder encrustation model, the PU/ATS reduced encrustation by 99.6 % (no infected) and by 86.7 % (infected) without organ damage. Therefore, the PU/ATS, by leveraging the hydration layer mechanism as an effective barrier, provides a practical and highly promising solution to combat encrustation and its associated urological complications.