Hydrophilic-antimicrobial dual-function modification of TPU catheter based on sodium alginate and cationic composite coating

This study investigates the clinical challenges associated with conventional catheters, particularly bacterial adhesion and catheter-associated infections (CAI), which are exacerbated by surface hydrophobicity. To address these issues, a functional modification strategy for thermoplastic polyurethane (TPU) catheters was developed, leveraging the complexation between sodium alginate (SA) and the cationic antimicrobial agent poly (hexamethylene biguanide) hydrochloride (PHMB) to construct a dual-functional composite coating system with combined hydrophilicity and antibacterial properties. A hydrophilic coating was first formed on the TPU surface using 3-glycidoxypropyltrimethoxysilane (KH-560) and polyvinylpyrrolidone (PVP), significantly reducing surface hydrophobicity. Simultaneously, the anionic properties of SA were utilized to complex cationic antimicrobial agents, forming a long-lasting antibacterial functional layer. The modified catheter exhibited a reduction in the coefficient of friction from 1.3 to 0.03, corresponding to a 53 % improvement in lubricity. Compared to unmodified catheters, the coating introduction showed no significant impact on maximum tensile force or hardness, but slightly reduced the bending modulus, enhancing adaptability in vascular environments. Zone of inhibition assay confirmed the strong antimicrobial efficacy of the hydrophilic-antibacterial coating against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ). Additionally, cytocompatibility and hemocompatibility verified the biosafety of the modified catheters. By optimizing the composite coating modification, this study successfully achieved efficient synergy between hydrophilicity and antibacterial properties in TPU catheters, providing an innovative solution to reduce the risk of CAI.