Lipofection is the transformation of cells using liposomes. Liposomes are artificial phospholipid vesicles used to deliver a variety of molecules including DNA into the cells. Liposomes can be preloaded with DNA and are then fused with the protoplasts to release the content into the cell. Animal cells, yeast protoplasts, plant cells, bacteria are susceptible to liposome transformation.
Membrane – membrane fusion and endocytosis are two common methods by which the liposomes fuse with the cells. DNA in solution spontaneously complexes with liposomes. Liposomes are positively charged vesicles produced from acidic lipids such as phosphatidyl glycerol and phosphatidyl serine. The liposomes may be multi lamellar vesicles having a size of 0.1 to 10 micrometer or uni lamellar types having 20-25 nano meters size. The liposome containing DNA is prepared as water- in -oil emulsion through sonication of the phospholipids and aqueous buffer in organic solvent. The organic solvent is the evaporated to leave the emulsion of liposomes.
Liposomes can be targeted to cells using monoclonal antibodies .The monoclonal antibodies recognize the surface antigens of cells specifically and bind with them along with the liposomes. Destruction of the liposomes by the cell’s lysosomes is prevented by pre treating the cells with chemicals like chloroquinine, cytochalsin B, cholchicine etc. The transfer of DNA from the liposomes to the nucleus is not completely known.