Liposomes for use in gene delivery

Abstract

Liposomes have a wide array of uses that have been continuously expanded and improved upon since first being observed to self-assemble into vesicular structures. These arrangements can be found in many shapes and sizes depending on lipid composition. Liposomes are often used to deliver a molecular cargo such as DNA for therapeutic benefit. The lipids used to form such lipoplexes can be cationic, anionic, neutral, or a mixture thereof. Herein physical packing parameters and specific lipids used for gene delivery will be discussed, with lipids classified according to overall charge.

Figure 1

Certain amphipathic lipid molecules in aqueous solution spontaneously form leaflets, then bilayer membranes, and eventually liposomes.

Figure 2

Structures predicted by the packing parameter P.

Figure 3

The structure of DOTMA.

Figure 4

The structure of DOTAP.

Figure 5

The structure of DC-Chol.

Figure 6

The structure of DOSPA.

Figure 7

The structure of DOGS.

Figure 8

The structures of two neutral lipids. (a) DOPE (b) DOPC.

Figure 9

Anionic Lipids. (a) Phosphatidic acid (pH = 7). (b) Phosphatidylglycerol. (c) Phosphatidylserine.