Comprehensive Examination of Mesophases Formed by DMPC and DHPC Mixtures

• DOI: 10.1021/la050018t
• Publication Date: 2005-05-31T12:01:32Z
• Authors: Thad A. Harroun; Martin Koslowsky; Mu-Ping Nieh; Charles-François ...; V. A. Raghunathan; John Katsaras
• Keywords: Lamellar phase; Polarized light microscopy; Lyotropic

Mixtures of long- and short-chain phospholipids, specifically 14:0 6:0 phosphatidylcholines (DMPC DHPC), have been used successfully in NMR studies as magnetically alignable substrates for membrane-associated proteins. However, recent publications shown that the phase behavior these mixtures is much more complex than originally thought. Using polarized light microscopy small-angle neutron scattering, diagrams DMPC/DHPC at molar ratios 2, 3.2, 5 determined. Generally, temperatures below main-chain melting transition DMPC (T(M) = 23 degrees C), an isotropic disk-like micelles found. At high (T > 50 a lamellar consisting either multilamellar vesicles (MLV) or extended lamellae formed, which low lipid concentrations (e.g., MLV) coexists with excess water. intermediate concentrations, chiral nematic made up worm-like was observed.