Sunday, 23 December 2012

A Liposome Described In Details

By Anna Hernandez

A liposome, an artificial vesicle comprises a double layer of fatty acids. It may be used as tools utilized to administer nutrients and pharmaceutical drugs to your body systems. They may be made by disrupting some biological membranes which may somehow involve sonication.

Liposomes are usually made of natural phospholipids. Furthermore, they may also be made of mixed lipid chains containing surfactant properties. Such lipid chains may include egg phosphatidylethanolamine. The design for this vesicle may adopt surface ligands used for attaching to tissues that are not healthy.

There are quite different categories of these synthetic lipid laden vesicles. The major types of liposomes are multilamellar vesicle that is shortened as MLV, small unilamellar vesicle that is abbreviated as SUV, large one lamellar vesicle whose short form is LUV, and lastly the cochleate vesicle. This depends on their number of lamella.

These products should not be mixed up with micelles as well as reverse micelles. This is because they are closely similar in structure. The only difference between them is that liposomes are made of bilayer of lipids while micelles and reverse micelles are composed of monolayers of lipids.

The membrane of the structure comprises of phospholipids that alludes to the molecules having tail groups and head groups. Their heads get attracted to water. However, the tail is made of only a long chain of hydrocarbons hence usually get repelled by water.

Their hydrophilic heads do make up the outermost layers while their hydrophobic tails make up the inner layers. This is because their heads are attracted to water while their tails are resisted by water. However, in every cell, a layer of heads always faces outside, and gets attracted to the polarized environment. Other layer of heads faces inside cell, and gets attracted to water molecules found within the cell. However, hydrophobic tails of its outer layer face hydrophobic tails of inner layers, thus forming a dual layer structure.

Liposomes were designated by a British hematologist known as Dr. Alec Bangham in 1961 in the institution of Babraham at Cambridge. It was later published in the year 1964. They were clearly found to take after plasmalemma. This was evidenced by pictures that were formed by a microscope that Bangham had used.

They encapsulate an aqueous solution using a hydrophobic membrane. Water insoluble chemicals can easily pass through the membranes while the water-soluble ones not. However, dissolved hydrophilic solutes can readily pass through the hydrophilic heads. For this reason, it can be used to deliver both hydrophobic and hydrophilic molecules. It delivers its contents by fusing with other structures with bilayer walls such as cell membranes.

This vesicle is applied in drug plus gene delivery services. Drugs and DNA that are to be conveyed typically contain a pH that is suitable for the purposes of any liposome. The application in DNA conversion is known as lipofection. In addition, it is also used in conveying dyes to textiles, enzymes and nutritional supplements to foods, cosmetics to skin as well as pesticides to plants.

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