Nanoscale Calorimetry Reveals Higher Stability of Cholesterol Induced Nanoscale Domains in Lipid Bilayers

Membranes of all cells contain a significant fraction of phospholipids arranged in a self-assembled bilayer. This lipid bilayer forms a robust barrier to ions, proteins and other molecules, and separates the inside of the cell from the outside (plasma membrane), or compartmentalizes the cells (mitochondria). Embedded in the lipid bilayers are a large variety of glycoproteins, globular proteins, and membrane channels[1]. The way these molecules perform their functions is strongly dependent on their location and the mechanical and chemical properties of the lipid environment around them. In cellular membranes, it is believed that lipid rafts (small lipid domains enriched in cholesterol) act to hold membrane proteins together in a dynamic fashion[2,3]. The difference in the stability between the lipid rafts and the fluid bilayer is believed to be very small.