A Swollen Phase of Phospholipid Bilayers Induced by Pressure

Abstract

Temperature, pressure, and ethanol concentration dependence of the structure and dynamics of dipalmitoyl phosphatidylcholine (DPPC) aqueous solution were investigated by small-angle neutron scattering and neutron spin echo experiments. A swollen phase, in which the mean repeat distance of lipid bilayers is larger than these of the other phases, is found between the liquid-crystalline phase and the interdigitated gel phase. The nature of the swollen phase is similar to the anomalous swelling state observed above the main transition temperature.