Cationic liposome-mediated transfection with lipofectin™ reagent.

Since their original description, liposomes have been discussed as vehicles that could be used as carriers of pharmaceutically active agents (1), and their potential for use as carriers of genetic information has been examined (2,3). Some encouraging DNA-delivery results have been obtained; however, the methodology has had some fundamental diffkulties (4-8). Chief among these is that liposomes do not generally fuse with the target cell surface, but are taken up phagocytically, and the polynucleotides are subsequently subjected to the action of digestive enzymes in the lysosomal compartment. Another practical problem with conventional liposome technology results because the internal dimensions of typical liposomes may be too small to accommodate large macromolecules, such as DNA or RNA, resulting in low capturing efficiency. In addition, conventional liposomal methodology involves a relatively inconvenient multistep preparation procedure.