ABSTRACT
Many membranes that are composed of lipids and sterols (including model giant unilamellar vesicles (GUVs), cell-derived GUVs, and yeast vacuole membranes) spontaneously demix into two or more coexisting phases. A phase diagram is a record of the phases that are observed at each temperature and at each ratio of lipid species; tie lines contain information about the composition of the different phases. This chapter reviews experimental methods of identifying coexisting phases in GUVs, mapping phase diagrams, and identifying tie lines. It concludes with experimental caveats relating to GUV compositional variation, fabrication, probes, tension, solutions, and imaging.
