Synergistic dual-nanostructure antibacterial-antifouling coating for tracheostomy tubes to reduce ventilator-associated pneumonia

Objective

To develop a dual-nanostructure coating for tracheostomy tubes to prevent ventilator-associated pneumonia (VAP) by inhibiting bacterial biofilm formation through combined superhydrophobic antifouling and sustained silver ion (Ag⁺) release.

Methods

Mesoporous silica nanoparticles (MSNs) were functionalized with octyltriethoxysilane (OTES) for superhydrophobicity (water contact angle: 162.8 ± 1°, sliding angle: 3.1 ± 0.5°) and loaded with 5–10 nm Ag₂O nanoparticles. Stability was evaluated via sandpaper abrasion tests (15 cycles, 120 g load) and short-term immersion (24 h) in pH 2–13 solutions. In vitro evaluations included quantification of bacterial adhesion (P. aeruginosa, Escherichia coli, S. aureus; 1 × 10⁸ CFU/mL), biofilm analysis by SEM/CLSM, and CCK-8 cytotoxicity assays with NIH/3T3 fibroblasts. In vivo, an 8-pig VAP model with hourly P. aeruginosa inoculation (1 × 10⁶ CFU/mL) was used to assess tracheal biofilm thickness, lung bacterial load, and inflammatory infiltration via H&E staining.

Results

The coating retained superhydrophobicity after challenges, reduced bacterial adhesion by ≥90.2 % vs. uncoated controls in vitro with disrupted biofilms and >95 % cell viability. In pigs, it reduced tracheal biofilm thickness by 65 % (p < 0.05), lung bacterial load by 82 % (p < 0.01), and neutrophil infiltration (p < 0.05).

Conclusion

The Ag₂O-MSNs@OTES coating effectively combats VAP via synergistic effects, with favorable short-term stability, excellent biocompatibility, and low cost (<$5/tube), supporting its potential for clinical translation. Further long-term stability tests are required to validate performance over extended clinical use.