Effect of surface modification on aggregation of phospholipid vesicles.

Phospholipid vesicles have been extensively investigated because of their usefulness as models for biological membranes and their potential application as carriers for drug delivery. However, preparations of small sonicated vesicles tend to aggregate and fuse (on storage at room temperature and at 4 degrees C), resulting in significant changes in turbidity, rate of uptake by macrophage, and proton NMR linewidths. By modification of the surface of phospholipid vesicles with charged groups such as beta-aminogalactose that extend significantly from the vesicle surface, it is possible to obtain preparations that are stable for greater than 7 days.