1.2- Dioleoyl-3 -trimethylammonium

Chemicals L-a-phosphatidylcholine (Soy PC), 1,2-Dioleoyl-3-trimethylammonium-propane chloride salt (DOTAP), Polyethylene glycol 3350, Mg-ATP, trehalose (Avanti Polar Lipids, Alabaster, AL), Hanks Salt solution, Na HPO, KH PO, and carboxyfluorescein (Sigma-Aldrich, St. Louis, MO). 

On the basis of the interaction of metal ions and AV-pH and AV-log C plots (41, 43), we propose ionic structures for dioleoyl, egg, and di-palmitoyl lecithin monolayers represented in Figure 1. Schematically shown in Figure 1A is the internal salt linkage between the phosphate and trimethylammonium groups in dioleoyl lecithin, preventing the inter-... 

A Dioleoyl lecithin shows internal salt linkage between phosphate and trimethyl-ammonium groups. Broken lines in egg lecithin diagram represents weak interactions of phosphate with Ca2+ and trimethylammonium group. Solid line between Ca + and phosphate group in dipalmitoyl lecithin diagram represents strong interaction... 

Fig. 2 Chemical structures of the zwitterionic neutral lipids DOPC (1,2-dioleoyl-.s -glycero-3-phosphatidylcholine) and DOPE (l,2-dioleoyl-S7J-glycero-3-phosphatidylethanolamine) and the cationic lipids DOTAP (l,2-dioleoyl-3-trimethylammonium-propane, a UVL) and MVL5 (a custom-synthesized MVL)...

Lipofectin is the name of the liposome reagent available from Gibco BRL. It is a mixture of 5 mg DOTMA (N-[l-(2,3,-dioleyloxy) propyl]-A, A, TV-trimethylammonium chloride) and 5 mg dioleoyl phosphatidylethanolamine sonicated in 1 ml distilled water. 

Egg phosphatidylcholine (EPC), cholesterol (Ch), mPEG ggg-DSPE, l,2-dioleoyl-3-trimethylammonium-propane (DOTAP), Rhodamine-PE (Rh-PE), and phosphatidylthio-ethanolamine (DPPE-SH) (all from Avanti Polar Lipids). 

Liposomes. Liposomes are vesicles that consist of an aqueous compartment enclosed in a phospholipids bilayer. As they lack proteinaceous components, liposomes are not immunogenic. A broad variety of cationic liposomes containing eventually modified lipids have been used to deliver pDNA and mRNA for therapeutic utilizations. These formulations are usually based on a cationic lipid such as l,2-dioleol-3-trimethylammonium propane (DOTAP) and a fusogenic lipid such as l,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) [22,23]. Despite their ease of production and efficacy in vitro for transfecting cultured cells, cationic liposomes face toxicity issues in vivo [24,25]. Meanwhile, their heterogeneous size... 

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