CORRELATION BETWEEN PHYSICOCHEMICAL CHARACTERISTICS OF SYNTHETIC CATIONIC AMPHIPHILES AND THEIR DNA TRANSFECTION ABILITY

Liposomes formed with synthetic double-chain ammonium amphiphiles were used for DNA transfection into eukaryotic cells. We studied the correlation between the efficiency of various cationic amphiphiles in DNA transfection and their physicochemical properties. The efficiency of amphiphiles in the transfection was examined by the transient expression of beta-galactosidase from its cDNA in COS cells. Amphiphiles with a phase-transition temperature (T(c)) lower than 37-degrees-C, as measured by differential scanning calorimetry, could introduce DNA into the cells. Electron microscopic observation indicated that amphiphiles possessing DNA transfection ability form vesicular structures in aqueous solution. Thus, fluid and vesicular bilayer structures were much higher than rigid and helical bilayer structures regarding the effectiveness of amphiphiles in DNA transfection. The efficiency of didodecyl N-[p-(2-trimethylammonioethoxy)benzoyl]-L-glutamate bromide was the highest of all the synthetic amphiphiles examined.