Properties of cationic liposomes composed of cationic lipid YKS-220 havingan ester linkage: Adequate stability, high transfection efficiency, and low cytotoxicity

Cationic lipid N-[3-[2-(1,3-dioleoyloxy)propoxy-carbonyl]propyl]-N,N,N-trim ethylammonium iodide (YKS-220) having a symmetrical and biodegradable struc ture was employed for the preparation of cationic liposomes with dioleoylph osphatidylethanolamine (DOPE). The stability, transfection activity in seve ral cell lines and cytotoxicity of YKS-220 cationic liposomes were studied. It was found the YKS-220 cationic liposomes were very stable and their tra nsfection activity remained even after storage at 4 degrees C for 12 months . The transfection activity of these liposomes was assayed using CHO, COS, and HepG2 cells and found to be comparable with, or better than, that of ot her cationic liposomes, such as N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimeth ylammonium methylsulfate (DOTAP) liposome, N-[1-(2,3-dioleyloxy)propyl]-N,N ,N-trimethylammonium chloride (DOTMA) liposome (Lipofectin(R)), and 2,3-dio leyloxy-N-[2-(sperminecarboxamido)ethyl]-N,N-dimethyl-1-propanaminium trifl uoroacetate (DOSPA) liposome (LipofectAMINE(TM)). In addition, the cytotoxi city of YKS-220 cationic liposomes was far lower than that of other cationi c liposomes.