Headgroup hydration in egg-lecithin multibilayers affects the behaviour of DPH probes

Abstract

Angle-resolved fluorescence depolarization experiments were carried out on DPH molecules embedded in egg-licithin bilayers of different water contents. It was found that the order parameter P2 of the absorption moment is significantly higher than that of the emission moment and that the difference increases on hydrating the lecithin headgroups. The changes in the order parameter P2 and P4 of the DPH molecules induced by hydration are consistent with X-ray diffraction data. Furthermore the reorientational motions of the DPH molecules were found to become faster with increasing hydration.