A spermine-deoxycholic acid conjugate based lipid as a transfecting agent

Deoxycholic acid-spermine conjugate (DAS), which is composed of natural components (deoxycholic acid and spermine), was incorporated in liposomes and evaluated for its interaction with plasmid DNA (pDNA) and in vitro transfection efficiency. Electromicrographs demonstrated that DAS-pDNA complexes are spherical, compact and electronically dense compared to the toroidal shapes formed by the monovalent lipid 1,2-dioleoyl-3-trimethylammonium propane (DOTAP) and pDNA. In comparison to the singly charged, non-cholesterol based lipid (DOTAP), the multivalent lipid DAS had similar transfection efficiency in two cell lines. The monovalent sterol, deoxycholic acid propyldiamine conjugate (DAP) was not effective as a transfecting agent. This suggests that multivalent facial amphiphiles such as DAS may serve as excellent candidates for non-viral gene transfer and warrant further study.