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Aqueous compartments enclosed by lipid bilayer membranes; liposomes are also known as lipid vesicles. Phospholipid molecules consist of an elongated nonpolar (hydrophobic) structure with a polar (hydrophilic) structure at one end. When dispersed in water, they spontaneously form bilayer membranes, also called lamellae, which are composed of two monolayer layer sheets of lipid molecules with their nonpolar (hydrophobic) surfaces facing each other and their polar (hydrophilic) surfaces facing the aqueous medium. The membranes enclose a portion of the aqueous phase much like the cell membrane which encloses the cell; in fact, the bilayer membrane is essentially a cell membrane without its protein components.

Liposomes are often used to study the characteristics of the lipid bilayer. Properties of liposomes have been characterized by a variety of techniques: molecular organization by x-ray diffraction, nuclear magnetic resonance, electron paramagnetic resonance, and Raman spectroscopy; melting behavior (that is, crystal to liquid-crystal transition) by calorimetry; net electric surface charge by microelectrophoresis; size by light scattering and electron microscopy. See Lipid

Liposomes have numerous uses as biochemical and biophysical tools: (1) as vehicles for the delivery of both water- and of oil-soluble materials to the cell; (2) as immunological adjuvants; (3) as substrates for the study of membrane properties such as rotational or translational diffusion in the plane of the membrane; and (4) as intermediates in the construction of bilayers large enough for the study of electrical properties of membranes. See Cell membranes

References in periodicals archive ?
This unique ability potentially allows the user to probe whether nanoscale drug delivery structures such as liposomes vary in their contents: Empty liposomes may have a lower RI (light scattering power) than those loaded with a higher RI material.
AbboMax offers various preformed liposome reagents with a large number of common lipid compositions to support the needs of research organizations involved in liposome drug delivery.
We have shown that liposomes are destroyed before they enter the skin or very soon after.
Alternatively, lipid-soluble substances may be complexed with cyclodextrins and then encapsulated within the aqueous compartment of liposomes and nanoliposomes.
Ginseng changes the flow behavior of lecithin liposomes.
It may be concluded that mannosylated liposome encapsulated QC not only prevented cerebral ischemia and reperfusion induced lipid peroxidation and cerebral edema development but also protected cerebral endogeneous antioxidant defence in young and old rat brain) This approach of delivering a non toxic herbal origin antioxidant (quercetin) to the brain offers the potential clinical application in human degenerative diseases in future)
Liposomes and lipid-based drug delivery systems have been used for the delivery of relatively large DNA and RNA-based drugs, including plasmids, antisense ON and ribozymes.
Figure 5b is an optical florescence micrograph of the liposomes encapsulating florescent dye flowing through the channel with a vacuum pressure of 5 cm Hg measured at the pump.
Phase I Study of Liposome Encapsulated Mitoxantrone (LEM) in Patients with Advanced Cancers (poster presentation)
At Cornell University's Food Research Laboratory in Geneva, New York, chemistry professor Richard Durst has been working on using liposomes to deliver markers that reveal the presence of E.
The sensor, which employs liposomes, has been developed at Cornell University's Department of Food Science and Technology.
NEW YORK - L'Oreal's Plenitude, France's leading skin care line, is following up its initial launch last September with the introduction of Action Liposomes daily skin care cream.