PHYSICOCHEMICAL CHARACTERISTICS OF LIPOSOMES FORMED WITH INTERNAL WOOL LIPIDS

The bilayer-forming capability of internal wool lipids and their physi cochemical properties were studied in an attempt to enhance our unders tanding of the lipid structure present in wool and other keratinized t issues. Internal wool lipids were extracted and analyzed, and the mixt ure obtained [sterol esters (10%), free fatty acids (24%), sterols (11 %), ceramides (46%), and cholesteryl sulfate (9%)] was shown to form s table liposomes. A phase-transition temperature of 60 degrees C was ob tained from nuclear magnetic resonance spectra for this lipid mixture. The spontaneous permeability of these vesicles was lower than that of phosphatidylcholine liposomes bur slightly higher than that of the ve sicles formed with lipids extracted from other keratinized tissues wit h higher amounts of cholesterol. The transmission electron micrographs showed large vesicular aggregates of approximately 300 nm, which seem to be made up of smaller structures of approximately 20 nm in size. T his particular structure could account for the large diameters and sma ll internal volumes found by dynamic light-scattering and spectrofluor ometric measurements.