The state of water in lipidic mesophase*

Water is the most ubiquitous and essential liquid on earth, and it is fundamental to the existence of life. Many biological processes take place in crowded aqueous surroundings and water in living cells can be considered as confined water. However, water behaves differently under confinement with respect to the crystallization and the molecular dynamics compared to those in the bulk. Especially in biological systems, the role of confined water is of crucial importance though still far from fully understood. Here I will present our recent studies on water under soft confining media provided by lipidic mesophase (LMP). Formerly in our group, an unfrozen lipid was synthesized which opens the gate for the study of water in LMPs at subzero temperatures. Yet, the complex synthetic procedures with low yields narrows the large-scale application. We recently discoveried a commercially available lipid, phytantiol, which gives the access to the liquid water in LMPs at subzero temperatures. I will first discuss the crystallization and dynamics of water confined in an unfrozen LMP based on phytantriol at subzero temperatures. Then I will discuss the state of water in lipidic mesophase during the phase transition from bicontinuous cubic phase to reverse hexagonal phase.