Phase behavior of lipids

Muller M and Sohiok M 1998 Caloulation of the phase behavior of lipids Phys. Rev. E 57 6973... 

Kenworthy AK, et al. Structure and phase behavior of lipid suspensions containing phospholipids with covalently attached poly (ethylene glycol). Biophys J 1995 68 1903. 

Phase behavior of lipid mixtures is a much more difficult problem, due to nonideal mixing of lipid components. Ideal mixing implies like and unlike lipids have the same intermolecular interactions, while nonideal mixing results from differential interactions between lipid types. If the difference is too great, the two components will phase separate. While phase separation and lateral domain formation have been observed in many experiments, we lack a molecular-level physical description of the interactions between specific lipids that cause the macroscopic behavior. The chemical potential of a lipid determines phase separation, as phase coexistence implies the chemical potential of each type of lipid is equal in all phases of the system [3,4],... 

Bouwstra, J.A., et al. 2001. Phase behavior of lipid mixtures based on human ceramides Coexistence of crystalline and liquid phases. J Lipid Res 42 1759. 

Eeigenson GW. Phase behavior of lipid mixtures. Nat. Chem. Biol. 2006 2 560-563. 

Within the last decade, scientists have recognized that roughly 25-50% of the lipids in a typical biomembrane do not form stable bilayer phases when they are purified and hydrated under normal cellular conditions (8). The prevalence of nonlamellar-prone lipids in biomembranes has stimulated research on the phase behavior of lipids and has led to suggestions that nonlamellar-prone lipids participate in essential cellular functions (2, 8). This theory has been supported by experiments that suggest that at least some cells have metabolic mechanisms that act to regulate the nonlamellar-prone lipids in the bilayers (7, 9, 10). 

W.P. Williams and P.J. Quinn (1987) The phase behavior of lipids in photosynthetic membranes. J. Bioenerg. Biomembr. 605-624. 

V. Phase Behavior of Lipids and Membrane Domain Formation... 

V. PHASE BEHAVIOR OF LIPIDS AND MEMBRANE DOMAIN FORMATION... 

Systematic studies of the phase behavior of lipid-surfactant systems have been performed particularly on mixtures of surfactants of the Ci2EOn type and phosphatidylcholines with different chain lengths and saturation [109-113]. The phase diagrams of these pseudo-binary mixtures in excess water are complicated and become even more so when the water content is varied. 

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