A liposome is a vesicle or small bubble that is composed of the same components as the cell membrane. Liposomes are drug depots that have been found to be useful in the treatment of cancer and various other diseases.
British haematologist Dr Alec D Bangham FRS was the first to discover liposomes at the Babraham Institute in Cambridge in 1961.
A derivative of a name
The name Liposome comes from the Greek words – “Lipos” (fat) and “Soma” (body). Liposomes can have different molecular sizes and thus can be unilamellar or multilamellar structures. Nanosomes are liposomes in the low nanometer range. However, nanosomes contain water, which liposomes do not.
Phospholipids are the building blocks of cell membranes, and these head-and-tail molecules also make up the liposome. The head group of the phospholipid attracts water, while the tail of the long hydrocarbon chain repels water. Liposomes include naturally occurring phospholipids that have mixed lipid chains. They can also be composed of DOPE (dioleoylphosphatidylethanolamine) as pure surfactants.
Liposomes are of three types:
· MLV or multilamellar vesicles
· SUV or small uni-lamellar vesicles
· LUV or large uni-lamellar vesicles
· Liposomes are widely used in drug preparation due to their unique properties.
· They are also used in various gene delivery applications such as lipofection where DNA is transformed into a host cell.
· They are used as carriers in textile dyeing
· They also act as carriers in plant pesticides, enzymes and various food additives and cosmetics.
· Liposomes are widely used in nano cosmetology and have several advantages.
· One of the strongest advantages of liposomes remains in targeting cancer.
Liposomes and nano liposomes do not form spontaneously. Liposomes can be synthesized by the phospholipid sonication process in water. Decreasing shear rates make way for multilamellar liposomes, and a continuous flow of high-shear ultrasound results in smaller unilamellar liposomes. Processes such as the Mozaffari method and extrusion are used to produce liposomes for human use.