title: In vitro determination of the solubility limit of cholesterol in phospholipid bilayers.
abstract: Cholesterol has limited solubility in phospholipid bilayers. The solubility limit is strongly dependent on the nature of the lipid with which the cholesterol is mixed while properties of the crystals formed can be modified by phospholipid-cholesterol interactions. In this review we summarize the various methods that have been developed to prepare hydrated mixtures of cholesterol and phospholipid. We point out some of the factors that determine the form adopted when cholesterol crystallizes in such mixtures, i.e. two- or three-dimensional, monohydrate or anhydrous. These differences can greatly affect the ability to experimentally detect the presence of these crystals in a membrane. Several methods for detecting cholesterol crystals are discussed and compared including DSC, X-ray and GIXRD diffraction methods, NMR and EPR spectroscopy. The importance of the history of the sample in determining the amount and nature of the cholesterol crystals formed is emphasized.
authors.affiliation: Department of Biochemistry, McMaster University, Hamilton, ON L8S 4K1, Canada. Electronic address: epand@mcmaster.ca.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Epand
authors.affiliation: Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Diana
authors.initials: D
authors.lastname: Bach
authors.affiliation: Faculty of Chemistry, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Ellen
authors.initials: E
authors.lastname: Wachtel
mesh_terms: D000818:Animals; D016477:Artifacts; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D002784:Cholesterol / Q000737:chemistry*; D006801:Humans; D008051:Lipid Bilayers / Q000737:chemistry*; D010743:Phospholipids / Q000737:chemistry*; D012995:Solubility
chemical_list: D008051:Lipid Bilayers; D010743:Phospholipids; D002784:Cholesterol
keywords: Cholesterol; Cholesterol crystals