Evidence for the hydration effect at the semiconductor phospholipid-bilayer interface by TiO2 photocatalysis.

The interactions of TiO2 with phospholipid bilayers found in cell membrane walls were observed to perturb the bilayer structure under UVA light irradiation. The structure changes in the phospholipid bilayers upon contact with TiO2 under light and in the dark were followed by X-ray diffraction. Hydration effects at the semiconductor-phospholipid interface played an important role in the degradation of dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE) bilayers taken as cell wall lipid bilayer models. Evidence is provided that the fluidity of the phospholipid bilayers plays a significant role when interacting in the dark with the TiO2 or in processes mediated by TiO2 under light irradiation.