[Study of vesicular lipid membranes by the ultrasound method]

The elastic properties of vesicular lipid membranes using high precision ultrasound velocity measurements in egg lecithin bilayer liposomes suspensions were studied. The temperature and K2SO4 concentration dependence of the hydrophobic part of the membrane elastic properties were obtained. The ionic strength dependence is shown to be linear and to change its sign at 27.5 degrees C. The value of molar volume of egg lecithin molecule hydrophobic part as calculated from acoustical and volumetric data is equal to (665 +/- +/- 63) cm3/mol and its adiabatic compressibility is equal to (58.7 +/- 5.9) . 10(-12) cm2/dyne.