Phase behaviour of dipalmitoyl phosphatidylcholine (DPPC)-cholesterol membranes

Abstract

We have determined the phase behaviour of dipalmitoyl phosphatidylcholine (DPPC)-cholesterol mixtures from small angle x-ray diffraction studies of oriented multilayers. A cholesterol induced modulated phase, denoted as Pβ, is obtained at intermediate cholesterol concentrations, which is distinct from the ripple (P_{\beta^{\prime }} ) phase found in earlier studies on similar systems. We also report some confocal fluorescence microscopy observations on giant unilamellar vesicles (GUVs) made from these mixtures.