An integrated lubricating and antibacterial hydrogel coating for the inner surface of medical catheters

Silicone rubber (PDMS) catheters are prone to tissue friction and bacterial infection due to their inherent hydrophobicity, yet achieving a durable and functional coating on the inner lumen remains technically challenging. This study presents a multifunctional hydrogel coating designed for the inner wall of medical silicone tubing to address these issues. The coating, composed of PHEMA-PVP-glycerol, was applied via selective benzophenone pretreatment, followed by UV curing. Systematic optimization revealed that a 40% glycerol content achieves an optimal balance of properties, yielding strong interfacial adhesion (5B), moderate hydrophilicity (WCA ∼33.7°), and excellent lubricity with a stable friction coefficient of approximately 0.18. The coated lumen demonstrates stable hydrophilicity (contact angles of 30°-44° against various biofluids) and maintains structural integrity with sustained low friction (∼0.20) even after 7 days of dynamic fluid flushing. Furthermore, the hydrogel network serves as an effective carrier for iodine, imparting potent and controllable antibacterial activity (achieving up to a 96.1% bactericidal rate against E. coli) without compromising the coating's lubricity or biocompatibility. This integrated coating strategy, combining durable lubrication with a sustained antibacterial effect, offers a promising surface engineering solution to enhance both the infection resistance and patient comfort of indwelling medical catheters.