Catheter associated urinary tract infection (CAUTI) presents a significant health problem worldwide and is associated with increased morbidity and mortality. Herein, a silver-polytetrafluoroethylene (Ag-PTFE) nanocomposite coating for catheters was developed via a facile wet chemistry method. Benefiting from the synergistic effect of Ag and PTFE, the as-prepared Ag-PTFE coated catheter exhibited enhanced antibacterial and anti-adhesive activities against two CAUTI-associated strains: E. coli WT F1693 and S. aureus F1557. Compared to the uncoated commercial silicone catheters and the Ag coated catheters, the Ag-PTFE coated catheters were able to reduce bacterial adhesion by up to 60.3% and 55.2%, respectively. The Ag-PTFE coated catheters also exhibited strong antibiofilm activity, reducing biofilm coverage by up to 97.4% compared with the commercial silicone catheters. In an in vitro bladder model, the Ag-PTFE coated catheter displayed excellent anti-infection efficacy against bacteriuria, extending the lifetime of silicone catheters from a mean of 6 days to over 40 days. The Ag-PTFE coating also showed good biocompatibility with fibroblast cells in culture, making it a prospective strategy to overcome current challenges in CAUTI.

The interaction energy between bacteria and substrata with different surface energies was modelled by the extended DLVO (Derjaguin, Landau, Verwey and Overbeek) theory. The modeling results revealed that the interaction energy has a strong correlation with the CQ (Chen and Qi) ratio, which is defined as the ratio of the Lifshitz–van der Waals (LW) apolar to the electron donor surface energy components of substrata. Both modeling and experimental results with different bacteria including P. fluorescens, Cobetia marina and Vibrio alginolyticus demonstrated that if the LW surface energy of bacteria is larger than that of water, which is the case for most bacteria, the number of adhered bacteria decreases with a decreasing CQ ratio while bacterial removal rate increases with a decreasing CQ ratio. However, if the LW surface energy of bacteria is less than that of water, the opposite results are obtained. The CQ ratio gives a clear direction for the design of anti-biofouling and biofouling-release coatings through surface modification.

Catheter-associated urinary tract infections (CAUTIs) are among the most common hospital-acquired infections, leading to increased morbidity and mortality. A major reason for this is that urinary catheters are not yet capable of preventing CAUTIs. To develop an anti-infective urinary catheter. An efficient silver-polytetrafluoroethylene (Ag-PTFE) nanocomposite coating was deposited on whole silicone catheters, and two in-vitro bladder models were designed to test antibacterial (against Escherichia coli) and anti-encrustation (against Proteus mirabilis) performances. Each model was challenged with two different concentrations of bacterial suspension. Compared with uncoated catheters, coated catheters significantly inhibited bacterial migration and biofilm formation on the external catheter surfaces. The time to develop bacteriuria was an average of 1.8 days vs 4 days and 6 days vs 41 days when the urethral meatus was infected with 106 and 102 cells/mL, respectively. For anti-encrustation tests, the coated catheter significantly resisted encrustation, although it did not strongly inhibit the increases in bacterial density and urinary pH. The time to blockage, which was found to be independent of the initial bacterial concentration in the bladder, was extended from 36.2±1.1 h (uncoated) to 89.5±3.54 h (coated) following bacterial contamination with 103 cells/mL in the bladder. Moreover, the coated catheter exhibited excellent biocompatibility with L929 fibroblast cells. Ag-PTFE coated Foley catheters should undergo further clinical trials to determine their ability to prevent CAUTIs during catheterization.