STRUCTURAL CHARACTERIZATION OF ORGANIZED SYSTEMS OF POLYSACCHARIDES AND PHOSPHOLIPIDS BY LIGHT-SCATTERING SPECTROSCOPY AND ELECTRON-MICROSCOPY

Biovectors are recently developed nanoparticles intended to be used as drug carriers and in the formulation of vaccines. The Biovectors are composed of a polysaccharide core to which phospholipids and cholester ol can be added, The cores are prepared by disruption of a gel of cros s-linked maltodextrins, and can have a positive, neutral or negative c harge depending on the grafting ionic ligands used. In this study stat ic and dynamic light scattering measurements were combined to characte rize the structure of these Biovectors. Transmission electron microsco py was also used. The present work, carried out with positively charge d Biovectors in PBS (phosphate buffer saline) and phosphate buffer, po ints towards a microgel like structure to the polysaccharide fragments of these Biovectors and a spherical geometry with radius approximate to 50 nm. The influence of lipid composition on Biovectors size and de nsity was also studied. The use of transmission electron microscopy gi ves first evidence for a structure consisting of several phospholipid bilayers surrounding a polysaccharide core, This organized lipidic env ironment is suitable for hydrophobic drug interaction and membrane pro teins insertion, The formulation of a stable, highly controlled drug d elivery system or vaccine formulation is implicated. (C) 1997 Elsevier Science Ltd.