title: DOTAP/DOPE and DC-Chol/DOPE lipoplexes for gene delivery studied by circular dichroism and other biophysical techniques.
abstract: Cationic liposomes give rise to stable complexes with DNA molecules (lipoplexes) that are of great interest for gene delivery applications. In particular, liposomes made up by a cationic lipid (DOTAP or DC-Chol) and a zwitterionic lipid (DOPE), produce stable adducts with single and double-stranded DNA oligonucleotides. Formation of these lipoplexes has been further addressed here by circular dichroism spectroscopy (CD) and by other independent biophysical methods. Titration of DNA oligonucleotides with cationic liposomes resulted into significant modifications of their circular dichroic bands. Such spectral modifications were ascribed to progressive DNA condensation and loss of native conformation, as a consequence of the electrostatic interactions taking place between the phosphate groups of DNA and the positively charged head groups of cationic lipids. In all cases, the loss of the CD feature characteristic of the native DNA conformation closely matched the inflection point of Zeta potential profiles. The resulting adducts showed peculiar and non-canonical CD spectra, while exhibiting appreciable stability at physiological pH.
authors.affiliation: Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Florence, Italy. ciani@csgi.unifi.it
authors.forename: Laura
authors.initials: L
authors.lastname: Ciani
authors.forename: Angela
authors.initials: A
authors.lastname: Casini
authors.forename: Chiara
authors.initials: C
authors.lastname: Gabbiani
authors.forename: Sandra
authors.initials: S
authors.lastname: Ristori
authors.forename: Luigi
authors.initials: L
authors.lastname: Messori
authors.forename: Giacomo
authors.initials: G
authors.lastname: Martini
mesh_terms: D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D002412:Cations; D002417:Cattle; D002784:Cholesterol / Q000031:analogs & derivatives* / Q000494:pharmacology; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D005229:Fatty Acids, Monounsaturated / Q000494:pharmacology*; D005456:Fluorescent Dyes / Q000494:pharmacology; D018014:Gene Transfer Techniques; D008055:Lipids / Q000737:chemistry; D008081:Liposomes / Q000737:chemistry / Q000378:metabolism; D008956:Models, Chemical; D010714:Phosphatidylethanolamines / Q000494:pharmacology*; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology*; D013696:Temperature
chemical_list: C410262:1,2-dioleoyl-glycero-3-phosphatidyl ethanolamine; D002412:Cations; D005229:Fatty Acids, Monounsaturated; D005456:Fluorescent Dyes; D008055:Lipids; D008081:Liposomes; D010714:Phosphatidylethanolamines; D000644:Quaternary Ammonium Compounds; C070648:3-(N-(N',N'-dimethylaminoethane)carbamoyl)cholesterol; D004247:DNA; D002784:Cholesterol; C070046:1,2-dioleoyloxy-3-(trimethylammonium)propane