Inhibition of biofilm formation on ventilation tubes by surface modification

Aim: The purpose of this study was to modify the surface characteristics of a ventilation tube (VT) with polyethylene glycol (PEG) coating and to evaluate the effect on biofilm formation. Materials and Methods: VTs made of polyethylene were coated with PEG. Streptococcus pneumonia R6 strain was used and a crystal violet assay was carried out to measure the in vitro and in vivo biofilm formation of rats bearing VTs. Results: In the in vitro experiment, the optical density of the uncoated VT was 0.34±0.09 and the optical density of the PEGgrafted VT was 0.22±0.06 (p<0.05). In the in vivo experiment, the optical density of the uncoated VT was 0.54±0.12 and that of the PEG-grafted VT was 0.32±0.13 (p<0.05). Scanning electron microscopy showed that surface modification, roughness and hydrophilic characteristics improved and biofilm formation decreased. Conclusion: The reduced biofilm formation on the VT may be explained by the alteration of surface tension and roughness induced by PEG coating.