Phase separation and critical phenomena in biomimetic ternary lipid mixtures

Lipid phase behaviour in biomimetic ternary mixtures has become a rich area of research and this review will provide a background to the many studies recently carried out, describing important advancements and future prospects for the field. In the liquid crystal community lipids are traditionally interesting as lyotropic materials and in this sense a large amount of work has been carried out on different systems. This paper will not focus on lyotropic phases but instead will concentrate on the thermotropic phase behaviour of ternary lipid mixtures. We will discuss thermotropic phase diagrams and critical phenomena in these systems, including their relationships to biological membranes. Interest in the links between lipid thermodynamics and cell function has grown steadily over the past three decades and most of the recent work in these areas has been motivated by a desire to link the phase behaviour of simple lipid mixtures to lateral organisation in the cell membrane. The literature in this field is extensive and can be intimidating; however, there are still unanswered fundamental questions. As important biological molecules, lipids have the potential to link many interesting physical ideas to how organisms function on a basic level and are certainly worthy of significant attention.