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New page: A '''liposome''' is microscopic, fluid-filled pouch whose walls are made of layers of phospholipids identical to the phospholipids that make up cell membranes. Liposomes are us...
A '''liposome''' is microscopic, fluid-filled pouch whose walls are made of layers of [[phospholipid]]s identical to the [[phospholipid]]s that make up [[cell membrane]]s. Liposomes are used to deliver certain [[vaccine]]s, [[enzyme]]s, or drugs (e.g., insulin and some cancer drugs) to the body. When used in the delivery of certain cancer drugs, liposomes help to shield healthy cells from the drugs' toxicity and prevent their concentration in vulnerable tissues (e.g., the [[kidney]]s, and [[liver]]), lessening or eliminating the common side effects of nausea, fatigue, and hair loss. Liposomes are especially effective in treating diseases that affect the [[phagocyte]]s of the [[immune system]] because they tend to accumulate in the [[phagocyte]]s, which recognize them as foreign invaders. They have also been used experimentally to carry normal [[gene]]s into a cell in order to replace defective, disease-causing [[gene]]s . Liposomes are sometimes used in cosmetics because of their moisturizing qualities.
Liposomes were first produced in England in 1961 by Alec D. Bangham, who was studying [[phospholipid]]s and blood clotting. It was found that [[phospholipid]]s combined with water immediately formed a sphere because one end of each molecule is water soluble, while the opposite end is water insoluble. Water-soluble medications added to the water were trapped inside the aggregation of the hydrophobic ends; fat-soluble medications were incorporated into the [[phospholipid]] layer.
In some cases liposomes attach to [[cellular membrane]]s and appear to fuse with them, releasing their contents into the cell. Sometimes they are taken up by the cell, and their [[phospholipid]]s are incorporated into the [[cell membrane]] while the drug trapped inside is released. In the case of phagocytic cells, the liposomes are taken up, the [[phospholipid]] walls are acted upon by [[organelle]]s called [[lysosome]]s, and the medication is released. Liposomal delivery systems are still largely experimental; the precise mechanisms of their action in the body are under study, as are ways in which to target them to specific diseased tissues.
==See Also==
*[[gene therapy]]
[[Category:Cellular Biology]]
Liposomes were first produced in England in 1961 by Alec D. Bangham, who was studying [[phospholipid]]s and blood clotting. It was found that [[phospholipid]]s combined with water immediately formed a sphere because one end of each molecule is water soluble, while the opposite end is water insoluble. Water-soluble medications added to the water were trapped inside the aggregation of the hydrophobic ends; fat-soluble medications were incorporated into the [[phospholipid]] layer.
In some cases liposomes attach to [[cellular membrane]]s and appear to fuse with them, releasing their contents into the cell. Sometimes they are taken up by the cell, and their [[phospholipid]]s are incorporated into the [[cell membrane]] while the drug trapped inside is released. In the case of phagocytic cells, the liposomes are taken up, the [[phospholipid]] walls are acted upon by [[organelle]]s called [[lysosome]]s, and the medication is released. Liposomal delivery systems are still largely experimental; the precise mechanisms of their action in the body are under study, as are ways in which to target them to specific diseased tissues.
==See Also==
*[[gene therapy]]
[[Category:Cellular Biology]]