BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 226, 450–455 (1996) ARTICLE NO. 1376 Stearylamine Liposome as a New Efficient Reagent for DNA Transfection of Eukaryotic Cells Die Wang,* Nai-he Jing,² and Qi-shui Lin* ,1 *State Key Laboratory of Molecular Biology and ² Laboratory of Cell Biology, Shanghai Institute of Biochemistry, Academia Sinica, 320 Yue Yang Road, Shanghai 200031, China Received July 22, 1996 The efficiency of stearylamine (SA) liposome in transfecting DNA into eukarytic cells was evaluated and compared with that of the Lipofectin reagent and the calcium phosphate transfection method. Results with the 21 cell lines tested varied, depending on the cell type. The overall indication was that SA liposomes had certain advantages over the Lipofectin reagent and both of them were superior to the calcium phosphate method, showing the greatest effect in 8 different cell lines, while the calcium phosphate method was the best in only 4 cell lines. There were 2 cell lines which could only be transfected by SA liposomes, another 2 only by the calcium phosphate method, but none depended solely on the Lipofectin reagent. The number of cell lines failed to be transfected was 2 for SA liposomes, 3 for calcium phosphate method, and 4 for the Lipofectin reagent. The advantage of the SA liposome method is discussed.  1996 Academic Press, Inc. A number of different methods had been developed in the past 20 years for the transfection of eukaryotic cells with nucleic acids. However, most of them suffer from one or more problems related to either cellular toxicity, poor reproducibility, inconvenience or inefficiency of DNA delivery. The method of using the Lipofectin reagent in the form of liposomes for transfection was a breakthrough of the liposome method and had been shown to have advantages over other methods (1) . Recently a number of cationic liposomes have been developed (2,3) . Although some of them are useful and even more effective than the Lipofectin reagent, they all contain synthetic organic compounds, which might restrict their in vivo usefulness. The SA liposome developed in our laboratory contains only dipalmitoyl-phosphatidylethanolamine and stearylamine, both of which are naturally occurring lipids. The high efficiency of SA liposomes in the transfection of eukaryotic cells and its low toxicity towards cells indicated that it may be a suitable reagent for nucleic acid transfections both in vitro and in vivo. The relative low cost of SA liposomes is another important consideration for routine experiments. In this communication, wider range of application of the method as compared with methods of calcium phosphate precipitation and the Lipofectin reagent is reported. Its value as eukaryotic cells transfection reagent was discussed. MATERIALS AND METHODS Materials DOPE, Penicillin-G, Streptomycin sulfate, Dubecco’s Modified Eagle’s Medium/Ham’s F12 1:1 mixture (DMEM/ F12)), CaCl 2 , Fetal Bovine Serum (FBS) were products of Sigma Co.; Stearylamine (SA) was purchased from Sigma Co. and purified according to (4); Lipofectin Reagent, Trypsin-EDTA (0.5% Trypsin and 5.3 mM EDTA-Na 4 ) were from GIBCO BRL Co., 2-mercaptoethanol from Fluka Co.; Hepes from Merck Co. and ONPG from Shanghai Dong Feng Biochemical Reagent Factory. All the other reagents were of analytical grade. Plasmids PCH 110 and PSK 110 were gifts from the Laboratory of gene expression and gene regulation of this Institute; Cell lines including CV-1, COS-7, CHO-K1, Hela, HepG2, MCF7, NIH3T3, Balb/c 3T3, NRK49F, WI38, NB41A3, Neuro2a, NB-1, PA-1, P19, PC12, C6, U251MG, and B16F10 were obtained from American Type Culture Collection, GR2H6 and GR3E5 are 1 Corresponding author. Fax: /8621 6433 5474/8357. 0006-291X/96 $18.00 Copyright  1996 by Academic Press, Inc. All rights of reproduction in any form reserved. 450