Synergistic antibacterial, anti-adhesion, and lubricating hydrogel coating with carbon quantum dots for urinary catheters: A multifaceted strategy against catheter-associated infections.

Urinary catheters (UCs) encounter persistent challenges, including catheter-associated urinary tract infections (CAUTIs) and friction-induced tissue damage. Here, we developed multifunctional carbon quantum dots (CQDs) - polyacrylic acid (PAA) - polyethylene glycol (PEG) - poly-N-isopropyl acrylamide (PNIPAM) (CAPPN) hydrogel coatings for polyvinyl chloride (PVC) UCs, which integrated CQDs with interfacial engineering to achieve synergistic antibacterial, anti-adhesion, and lubrication properties. The hydrothermally synthesized CQDs (3.74 ± 0.94 nm, ζ = +27.6 mV) effectively disrupted bacterial membranes through electrostatic interactions. Additionally, polydopamine (PDA) bridging and UV-induced polymerization facilitated robust hydrogel adhesion (3.11 N·cm peel strength) and mechanical resilience (4.61 MPa tensile strength, 1144.72 % elongation). Compared to the bare UCs, the CAPPN hydrogel-coated UCs demonstrated a 33 % reduction in friction (coefficient: 0.14 vs. 0.21) and enhanced hydrophilicity (water contact angle: 20.32° vs. 90.56°) due to the grafting of PAA/PEG/PNIPAM. Furthermore, the CAPPN hydrogel-coated UCs achieved significant antibacterial efficacy against Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), and Klebsiella pneumoniae (K. pneumoniae) (81.4 %, 79.4 %, and 77.1 % inhibition, respectively) and achieved anti-adhesion rates of 82.9 % for E. coli and 98.2 % for Staphylococcus aureus (S. aureus), with complete biofilm suppression. This multi-modal design, which combined CQDs-driven bactericidal action, molecular anti-adhesion architecture, and surface lubrication, comprehensively addressed the challenges posed by CAUTIs. Additionally, the CAPPN hydrogel-coated UCs demonstrated exceptional cytocompatibility and hemocompatibility, thereby ensuring clinical biocompatibility and biosafety. The CAPPN hydrogel-coated UCs signify a substantial advancement in the functionalization of medical devices.