title: Transition from a normal to inverted cylinder for an amidine-bearing lipid/pDNA complex and its excellent transfection.
abstract: A cationic lipid (TRX) having an amidine headgroup was synthesized, and a lipoplex (i.e., plasmid DNA+lipid complex) was prepared from the mixture of TRX and two other neutral colipids. Small-angle X-ray scattering showed that the addition of DNA induced a structural transition from normal to inverted hexagonally packed cylinders. Transmission electron microscopy showed a threadlike micelle was transformed to a spherical micelle about 50-200 nm in diameter by adding DNA. A combination of these results leads to the conclusion that the complexed DNA is hexagonally packed (or condensed) into spherical aggregates. The size and morphology are believed suitable for endocytosis uptake or vesicle fusion. The complex made from pDNA (pEGFP-C1) and TRX was transfected to Hep G2. Flow cytometry and confocal microscopy showed that the present system expressed green fluorescence protein (GFP) more than a conventional transfection reagent. Additionally, TRX was less cytotoxic than other transfection reagents. This paper presents the attractive possibility of the amidine group for a transfection device.
authors.affiliation: Terumo Corporation R & D Center, 1500 Inokuchi, Nakai-machi, Ashigarakami-gun Kanagawa, 259-0151, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Koiwai
authors.forename: Kenji
authors.initials: K
authors.lastname: Tokuhisa
authors.forename: Ryouji
authors.initials: R
authors.lastname: Karinaga
authors.forename: Yasuya
authors.initials: Y
authors.lastname: Kudo
authors.forename: Shota
authors.initials: S
authors.lastname: Kusuki
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Takeda
authors.forename: Kazuo
authors.initials: K
authors.lastname: Sakurai
mesh_terms: D000578:Amidines; D002412:Cations; D045744:Cell Line, Tumor; D049452:Green Fluorescent Proteins / Q000235:genetics; D006801:Humans; D008055:Lipids / Q000737:chemistry*; D008823:Micelles; D010316:Particle Size; D044367:Phase Transition; D010957:Plasmids / Q000737:chemistry*; D014162:Transfection / Q000379:methods*
chemical_list: D000578:Amidines; D002412:Cations; D008055:Lipids; D008823:Micelles; D049452:Green Fluorescent Proteins