High transfection efficiency and low toxicity cationic lipids with aminoglycerol-diamine conjugate

The solid phase synthesis of a library of aminoglycerol-diamine conjugate-based transfection agents having urea linkage between diverse length of diamines and various lengths of hydrophobic tails is described. These compounds were characterized and structure-activity relationships were determined for DNA binding and transfection ability when formulated as cationic liposomes. Cationic lipids with short spacer length and short hydrophobic tails bound to DNA and delivered DNA into HEK293 cells more efficient than those with longer ones. Transfection efficiency of some of the cationic liposomes was superior to that of the commercial transfection agents, Effectene, DOTAP and DC-Chol. The lipids 6Ab and 6Bb did not require the helper lipid DOPE to produce high-efficiency transfection of human cells while displaying minimal cytotoxicity. This suggests that these newly described aminoglycerol-based lipids should be very promising in liposome-mediated gene delivery and illustrate the potential of solid phase synthesis method for non-viral vector discovery.