Mussel-Inspired Sonochemical Nanocomposite Coating on Catheters for Prevention of Urinary Infections

Catheter-associated urinary tract infections are the most common hospital-acquired infections and cause patient discomfort, increased morbidity, and prolonged stays, altogether posing a huge burden on healthcare services. Colonization occurs upon insertion, or later by ascending microbes from the rich periurethral flora, and is therefore virtually unavoidable by medical procedures. Importantly, the dwell time is a significant risk factor for bacteriuria because it gives biofilms time to develop and mature. This is why we engineer antibacterial and antibiofilm coating through ultrasound- and nanoparticle-assisted self-assembly on silicone surfaces and validate it thoroughly in vitro and in vivo. To this end, we combine bimetallic silver/gold nanoparticles, which exercise both biocidal and structural roles, with dopamine-modified gelatin in a facile and substrate-independent sonochemical coating process. The latter mussel-inspired bioadhesive potentiates the activity and durability of the coating while attenuating the intrinsic toxicity of silver. As a result, our approach effectively reduces biofilm formation in a hydrodynamic model of the human bladder and prevents bacteriuria in catheterized rabbits during a week of placement, outperforming conventional silicone catheters. These results substantiate the practical use of nanoparticle–biopolymer composites in combination with ultrasound for the antimicrobial functionalization of indwelling medical devices.