High‐pressure differential thermal analysis of lamellar to lamellar and lamellar to non‐lamellar lipid phase transitions

Abstract

AbstractHydrated phospholipids, which provide model systems for lipid membranes, display a variety of polymorphic phases, depending on their molecular structure and environmental conditions. In this study, high hydrostatic pressure has been used as a physical parameter to study the thermodynamic properties and phase behaviour of phospholipid systems, and because high pressure is a characteristic feature of certain natural membrane environments. We built a new high‐pressure differential thermal analysis (DTA) apparatus, which allowed us to study the calorimetric properties and the temperature and pressure dependent phase behaviour of lipid systems up to temperatures of 360 K and pressures of 250 MPa. In particular, we focussed on the effect of pressure on lamellar to lamellar and on lamellar to non‐lamellar phase transitions of phospholipid systems, differing in lipid chain saturation and headgroup structure. The possible biophysical implications of this study are discussed.