Multiple cholesterol–phospholipid complexes in membranes

Previous work has implied the formation of ‘condensed complexes’ of cholesterol and phospholipids in monolayers at the air–water interface. The present study gives illustrative theoretical calculations of phase diagrams, concentration profiles, and average molecular areas when more than one complex is assumed to be present. It is shown that multiple complexes should be detectable experimentally under some but not all conditions. The relationship between condensed complexes in monolayers and bilayers is discussed.