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

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