Bio-inspired antibacterial coatings on urinary stents for encrustation prevention

Urinary tract infection (UTI) represents one of the most common nosocomial infections, which is mainly related to indwelling catheters or stents. In addition to the formation of biofilms to reduce antibiotic sensitivity, the urease-producing bacteria can also increase urine pH, causing Ca²⁺ and Mg²⁺ deposition and finally catheter obstruction. The prevention of UTIs and its complication (i.e., encrustation) thus is a great challenge in design of catheters and ureteral stents. In this work, a metal-catechol-assisted mussel chemistry (i.e., dopamine self-polymerization) was employed for surface functionalization of commercially available catheters with antimicrobial peptides (AMP), for the purpose of long-term anti-infection and encrustation prevention. To improve the stability of the polydopamine coating on polymeric stents, we used Cu²⁺-coordinated dopamine self-polymerization. Then, a cysteine-terminated AMP was introduced on the polydopamine coating through Michael addition. We found that the Cu²⁺-coordinated polydopamine coating showed improved stability and antibacterial effect. The cytotoxicity test confirmed that the bioinspired antibacterial coating showed good biocompatibility and no obvious toxicity. The results confirmed that the stents with AMP could in situ inhibit bacterial growth and biofilm formation, and finally reduce the deposition of struvite and hydroxyapatite crystals both in vitro and in vivo. We anticipate that this bioinspired strategy would develop a safe, stable and effective antibacterial coating on urinary tract medical devices for long-term bacterial inhibition and encrustation prevention.