what are liposomes?

Question

targeted drug delivery system

Answer 1

A liposome is a spherical vesicle with a membrane composed of a phospholipid bilayer used to deliver drugs or genetic material into a cell. Liposomes can be composed of naturally-derived phospholipids with mixed lipid chains (like egg phosphatidylethanolamine), or of pure components like DOPE (dioleolylphosphatidylethanolamine).

The lipid bilayer can fuse with other bilayers (e.g., the cell membrane), thus delivering the liposome contents. By making liposomes in a solution of DNA or drugs,(which would normally be unable to diffuse through the membrane), they can be (indiscriminately) delivered past the lipid bilayer.

The use of liposomes for transformation or transfection of DNA into a host cell is known as lipofection.

Liposomes can be created by sonicating phospholipids in water. Low shear rates create multilamellar liposomes, which have many layers like an onion. Continued high-shear sonication tends to form smaller unilamellar liposomes. In this technique, the liposome contents are the same as the contents of the aqueous phase.

Further advances in liposome research have been able to allow liposomes to avoid detection by the body's immune system, specifically, the cells of reticuloendothelial system (RES). These liposomes are known as "stealth liposomes", and are constructed with PEG (Polyethylene Glycol) as coating. The PEG coating, which is inert in the body, allows for longer circulatory life for the drug delivery mechanism. However, research currently seeks to investigate at what amount of PEG coating the PEG actually hinders binding of the liposome to the delivery site. In addition to a PEG coating, most stealth liposomes also have some sort of biological species attached as a ligand to the liposome in order to enable binding via a specific expression on the targeted drug delivery site.

Usefulness of liposomes are further expanded by the construction of immunoliposomes, where fragments of antibody against some specific target can be conjugated onto the liposome, thus achieve the desired effect of specific targeting.

Answer 2

A liposome is a spherical vesicle with a membrane composed of a phospholipid bilayer used to deliver drugs or genetic material into a cell. Liposomes can be composed of naturally-derived phospholipids with mixed lipid chains (like egg phosphatidylethanolamine), or of pure components like DOPE (dioleolylphosphatidylethanolamine).

The lipid bilayer can fuse with other bilayers (e.g., the cell membrane), thus delivering the liposome contents. By making liposomes in a solution of DNA or drugs,(which would normally be unable to diffuse through the membrane), they can be (indiscriminately) delivered past the lipid bilayer.

The use of liposomes for transformation or transfection of DNA into a host cell is known as lipofection.

Liposomes can be created by sonicating phospholipids in water. Low shear rates create multilamellar liposomes, which have many layers like an onion. Continued high-shear sonication tends to form smaller unilamellar liposomes. In this technique, the liposome contents are the same as the contents of the aqueous phase.

Further advances in liposome research have been able to allow liposomes to avoid detection by the body's immune system, specifically, the cells of reticuloendothelial system (RES). These liposomes are known as "stealth liposomes", and are constructed with PEG (Polyethylene Glycol) as coating. The PEG coating, which is inert in the body, allows for longer circulatory life for the drug delivery mechanism. However, research currently seeks to investigate at what amount of PEG coating the PEG actually hinders binding of the liposome to the delivery site. In addition to a PEG coating, most stealth liposomes also have some sort of biological species attached as a ligand to the liposome in order to enable binding via a specific expression on the targeted drug delivery site.

Usefulness of liposomes are further expanded by the construction of immunoliposomes, where fragments of antibody against some specific target can be conjugated onto the liposome, thus achieve the desired effect of specific targeting.

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Answer 3

A liposome is a spherical vesicle with a membrane composed of a phospholipid bilayer used to deliver drugs or genetic material into a cell. Liposomes can be composed of naturally-derived phospholipids with mixed lipid chains (like egg phosphatidylethanolamine), or of pure components like DOPE (dioleolylphosphatidylethanolamine).

The lipid bilayer can fuse with other bilayers (e.g., the cell membrane), thus delivering the liposome contents. By making liposomes in a solution of DNA or drugs,(which would normally be unable to diffuse through the membrane), they can be (indiscriminately) delivered past the lipid bilayer.

The use of liposomes for transformation or transfection of DNA into a host cell is known as lipofection.

Liposomes can be created by sonicating phospholipids in water. Low shear rates create multilamellar liposomes, which have many layers like an onion. Continued high-shear sonication tends to form smaller unilamellar liposomes. In this technique, the liposome contents are the same as the contents of the aqueous phase.

Further advances in liposome research have been able to allow liposomes to avoid detection by the body's immune system, specifically, the cells of reticuloendothelial system (RES). These liposomes are known as "stealth liposomes", and are constructed with PEG (Polyethylene Glycol) as coating. The PEG coating, which is inert in the body, allows for longer circulatory life for the drug delivery mechanism. However, research currently seeks to investigate at what amount of PEG coating the PEG actually hinders binding of the liposome to the delivery site. In addition to a PEG coating, most stealth liposomes also have some sort of biological species attached as a ligand to the liposome in order to enable binding via a specific expression on the targeted drug delivery site.

Usefulness of liposomes are further expanded by the construction of immunoliposomes, where fragments of antibody against some specific target can be conjugated onto the liposome, thus achieve the desired effect of specific targeting.

Answer 4

A spherical particle in an aqueous (watery) medium (eg, inside a cell) formed by a lipid bilayer enclosing an aqueous compartment. Microscopic globules of lipids are manufactured to enclose medications. The fatty layer of the liposome is supposed to protect and confine the enclosed drug until the liposome binds with the outer membrane of target cells. By delivering treatments directly to the cells needing them, drug efficacy may be increased while overall toxicity is reduced.
www.thebody.com/hivatis/glossary/l.html - Definition in context

Answer 5

A liposome is a spherical vesicle with a membrane composed of a phospholipid bilayer used to deliver drugs or genetic material into a cell. Liposomes can be composed of naturally-derived phospholipids with mixed lipid chains (like egg phosphatidylethanolamine), or of pure components like DOPE (dioleolylphosphatidylethanolamine).
en.wikipedia.org/wiki/Liposomes

Answer 6

What Are Liposomes