title: Structural dynamics and physicochemical properties of pDNA/DODAB:MO lipoplexes: effect of pH and anionic lipids in inverted non-lamellar phases versus lamellar phases.
abstract: Dioctadecyldimethylammonium bromide (DODAB):Monoolein (MO) lipoplexes have mainly been studied within the range of high molar ratios of DODAB, with noticeable transfection efficiencies in the Human Embryonic Kidney (HEK, a.k.a. 293T) cell line. In this work, we intend to study the effect of high MO content on the structure and physicochemical properties of pDNA/DODAB:MO lipoplexes to achieve some correlation with their transfection efficiency. Static/Dynamic Light Scattering and Cryo-TEM imaging were used to characterize the size/morphology of DNA/DODAB:MO lipoplexes at different DODAB:MO contents (2:1, 1:1, 1:2) and charge ratios (CRs) (+/-). Nile Red fluorescence emission was performed to detect changes in microviscosity, hydration and polarity of DNA/DODAB:MO systems. Lipoplexes stability at physiological pH values and in the presence of anionic lipids was evaluated by Förster Resonance Energy Transfer (FRET). Physicochemical/structural data were complemented with transfection studies in HEK cells using the β-galactosidase reporter gene activity assay. This work reports the coexistence of multilamellar and non-lamellar inverted phases in MO-richer lipoplexes (DODAB:MO 1:2 and 1:4), leading to transfection efficiencies comparable to those of multilamellar (DODAB-richer) lipoplexes, but at higher charge ratios [CR (+/-)=6.0] and without dose-effect response. These results may be related to the structural changes of lipoplexes promoted by high MO content.
authors: CFUM (Centre of Physics of the University of Minho), Department of Physics, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal.
authors: J P Neves
authors: JP
authors: Silva
authors: CFUM (Centre of Physics of the University of Minho), Department of Physics, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal.
authors: I M S C
authors: IM
authors: Oliveira
authors: CFUM (Centre of Physics of the University of Minho), Department of Physics, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal; CBMA (Centre of Molecular and Environmental Biology), Department of Biology, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal.
authors: A C N
authors: AC
authors: Oliveira
authors: CFUM (Centre of Physics of the University of Minho), Department of Physics, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal.
authors: M
authors: M
authors: Lúcio
authors: CBMA (Centre of Molecular and Environmental Biology), Department of Biology, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal.
authors: A C
authors: AC
authors: Gomes
authors: CFUM (Centre of Physics of the University of Minho), Department of Physics, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal.
authors: P J G
authors: PJ
authors: Coutinho
authors: CFUM (Centre of Physics of the University of Minho), Department of Physics, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal. Electronic address: beta@fisica.uminho.pt.
authors: M E C D Real
authors: ME
authors: Oliveira
mesh_terms: D004247:DNA / Q000737:chemistry*; D005989:Glycerides / Q000737:chemistry*; D057809:HEK293 Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D010957:Plasmids / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D014162:Transfection / Q000379:methods
chemical_list: D005989:Glycerides; D000644:Quaternary Ammonium Compounds; C015831:dimethyldioctadecylammonium; D004247:DNA; C005953:monoolein
keywords: Cryo-TEM; FRET; Light scattering; Lipoplexes; Nile Red; Transfection