(323f) Low Friction Mesoporous Titanium Dioxide Films Defending Against Escherichia coli

The geometrical strategy for designing low friction titanium dioxide (TiO₂) films that prevent Escherichia coli (E. coli) adhesion has been demonstrated in this study. The results show that settlement and adhesion of E. coli onto mesoporous TiO₂ films are significantly low, but high onto dense TiO₂. The resistance of mesoporous TiO₂ films against E. coli is related to the low friction surface (friction coefficient: 2.5×10^-3). There exists a strongly adsorbed “bound water” layer at the bottom of the TiO₂ surface, and weakly adsorbed “free water” on the upper layer of the TiO₂ surface. The existence of nanostructured pores on the “slippery” low friction mesoporous TiO₂ leads to two kinds of contacts for E. coli with the surface. Some of the E. coli have to overcome stronger interactions from the “bound water” layer, but the others just need to overcome lower interactions (14.9 nN) from the weakly adsorbed “free water” on the apex of nanostructured pores. However, on the homogeneous dense TiO₂ surface (friction coefficient: 7.1×10^-2), stronger interactions (57.4 nN) need to be conquered between all of the E. coli and the strongly adsorbed “bound water” layer on the TiO₂ surface. Meanwhile, the E. coli that is strongly attached on the “sticky” dense TiO₂ surface cannot easily be removed even by the dynamic rinse process. Therefore, the “slippery” low friction mesoporous TiO₂ has been shown to be a suitable surface for defending against the adhesion of E. coli. This is a geometrical approach that guides E. coli adsorption on the mesoporous TiO₂ surface with nanostructured pores. Therefore, these studies indicate that biocompatible mesoporous TiO₂ exhibits desirable bacteria-resistant properties for use in marine coatings and biomedical fields.