ObjectiveThe aim of this study was to assess the antibacterial activity against
Staphylococcus aureus and Pseudomonas
aeruginosa of two nanoparticle endotracheal tube coatings with
visible light-induced photocatalysis.MethodsTwo types of titanium dioxide nanoparticles were tested: standard anatase
(TiO2) and N-doped TiO2 (N-TiO2).
Nanoparticles were placed on the internal surface of a segment of commercial
endotracheal tubes, which were loaded on a cellulose acetate filter; control
endotracheal tubes were left without a nanoparticle coating. A bacterial
inoculum of 150 colony forming units was placed in the endotracheal tubes
and then exposed to a fluorescent light source (3700 lux, 300-700 nm
wavelength) for 5, 10, 20, 40, 60 and 80 minutes. Colony forming units were
counted after 24 hours of incubation at 37°C. Bacterial inactivation was
calculated as the percentage reduction of bacterial growth compared to
endotracheal tubes not exposed to light.ResultsIn the absence of light, no relevant antibacterial activity was shown against
neither strain. For P. aeruginosa, both coatings had a
higher bacterial inactivation than controls at any time point (p <
0.001), and no difference was observed between TiO2 and
N-TiO2. For S. aureus, inactivation was
higher than for controls starting at 5 minutes for N-TiO2 (p =
0.018) and 10 minutes for TiO2 (p = 0.014); inactivation with
N-TiO2 was higher than that with TiO2 at 20
minutes (p < 0.001), 40 minutes (p < 0.001) and 60 minutes (p <
0.001).ConclusionsNanosized commercial and N-doped TiO2 inhibit bacterial growth
under visible fluorescent light. N-TiO2 has higher antibacterial
activity against S. aureus compared to TiO2.