Thermo-induced dynamics of membranes and liquid crystals containing cholesterol derivatives

Membrane structural organization is an intrinsic property of cell membranes. Membrane dynamics provide a means by which changes in structure organization can be determined upon a change in the membrane internal or external environment. Cholesterol derivatives have been shown to influence thermo-stability of membranes. Moreover, it has been known that some these derivatives are capable of forming a liquid crystal state, called cholesterol liquid crystals (LCs). Cholesterol LCs have many potential applications to not only engineering fields but also studying of disease pathophysiology and drug delivery systems. Here, we investigated the effect of thermo-stress on dynamics of membrane and optical properties of LCs that contain cholesterol benzoate (Benzo) and oxidized cholesterols using Langmuir monolayer experiment and polarized light observation, respectively. We have (i) showed that membrane containing Benzo is thermo-responsive; and this thermo-sensitivity is significantly similar to that of oxy-cholesterol-containing membranes; (ii) estimated changes in gray-scale intensity of LCs containing cholesterol derivatives upon temperature change; (iii) discussed the relation and similarity between LC and membrane via molecular interaction. Our results are useful development of cholesterol oxidation detections and drug delivery systems.