INVESTIGATION ON THE MORPHOLOGY AND PROPERTIES OF AGGREGATED NATURAL PHOSPHOLIPIDS IN AQUOUS SYSTEM USING CRYO-TEM

Abstract

Cryogenic transmission electron microscopy (cryo-TEM) was used to investigate the aggregates morphology and properties of candle tree (Aleurites moluccana) endosperm, sesame (Sesamum indicum L. syn.) seeds, and coconut (Cocos nucifera) endosperm phospholipids in dilute aquous system. For candle tree endosperm, the micrographs show formation of planar bilayers and some aggregation of vesicles with droplet of lipids. Phospholipids from sesame seeds show formation of well-defined unilamellar vesicles, liposomes. After extrusion, the size can be reduced down to less than 50 nm with the wall still intact. Coconut endosperm phospholipids show formation of large cluster of aggregated vesicles which will be separated into small unilamelar vesicles and small clusters of vesicles upon extrusion. All aggregates from candle tree, sesame seed and coconut endosperm show unilamellarity of the aggregates wall. The micrographs also reveal the invaginated form of aggregates which clearly show that the bilayer constructing the wall is soft and can be easily bent by osmotic gradient.</p