Liposome and cell membranes

Fig. 6.3. Micelles, liposomes and cell membranes. Micelles are collections of lipid molecules that are relatively nonpolar internally and polar externally. This arrangement allows relative water-solubility of the micelle as a whole. Liposomes contain lipid molecules in a bilayer. They may be used as artificial vehicles for trapping and delivery of drugs to specific tissues. They are also useful as models of cell surfiice function. A real cell membrane is not only a lipid bilaycr, but also includes proteins, glycoproteins, glycolipids, and lipoprotein molecules. The glyco attachments on the outer surface may be important in labeling cells with specific cell-surfece properties.

This, then, is the key to how the pluronics stabilize liposomes and cell membranes. At low pressure, when the membrane would normally pull apart, pluronics insert and inaease the surface pressure. At high surface pressure, the polymer is ejected from the membrane onto the surface. Thus, a mechanism for membrane hole sealing can be envisaged. Under normal conditions, the pluronics are squeezed out of the membrane. If a hole is formed in the membrane, however, the polymer inserts into the membrane defect, keeping the membrane intact. 

Comparison between lipid bilayer, liposomes, and cell membranes 385... 

---

See also in sourсe #XX -- [ ]

---