1991/12/01 by M. Kummrow, W. Helfrich
Biochemistry, Genetics and Molecular Biology · Agricultural and Biological Sciences · #Lipid Membrane Structure and Behavior #Proteins in Food Systems #Protein Structure and Dynamics
paper · doi:10.1103/physreva.44.8356
We deform spherical giant vesicles made of lipid bilayers, egg yolk phosphatidylcholine (EYPC), 1,2-dilaureoyl-sn-3-phosphatidylcholine (DLPC), l-palmitoyl-2-oleoyl-sn-3-phosphatidylcholine (POPC), and digalactosyldiacylglycerol (DGDG), into prolate ellipsoids of revolution by means of alternating electric fields. The lateral tensions stretching the vesicle membrane are calculated from the Maxwell stress tensor and the eccentricity of the ellipsoid. The apparent increase of membrane area with tension, being due to a flattening of thermal undulations, permits us to determine the bending rigidities. We obtain 2.47\ifmmode×\else\texttimes\fi10^\mathrm\ensuremath-20 J for EYPC, 3.37\ifmmode×\else\texttimes\fi10^\mathrm\ensuremath-20 J for DLPC, 2.46\ifmmode×\else\texttimes\fi10^\mathrm\ensuremath-20 J for POPC, and 1.01\ifmmode×\else\texttimes\fi10^\mathrm\ensuremath-20 J for DGDG, with errors of up to 20%. These values are slightly smaller than those reported to date for the same materials.