title: Surface charge density determines the efficiency of cationic gemini surfactant based lipofection.
abstract: The efficiencies of the binary liposomes composed of 1,2-dimyristoyl-sn-glycero-3-phosphocholine and cationic gemini surfactant, (2S,3R)-2,3-dimethoxy-1,4-bis(N-hexadecyl-N,N-dimethylammonium)butane dibromide as transfection vectors, were measured using the enhanced green fluorescent protein coding plasmid and COS-1 cells. Strong correlation between the transfection efficiency and lipid stoichiometry was observed. Accordingly, liposomes with X(SR-1) > or = 0.50 conveyed the enhanced green fluorescent protein coding plasmid effectively into cells. The condensation of DNA by liposomes with X(SR-1) > 0.50 was indicated by static light scattering and ethidium bromide intercalation assay, whereas differential scanning calorimetry and fluorescence anisotropy of diphenylhexatriene revealed stoichiometry dependent reorganization in the headgroup region of the liposome bilayer, in alignment with our previous Langmuir-balance study. Surface charge density and the organization of positive charges appear to determine the mode of interaction of DNA with (2S,3R)-2,3-dimethoxy-1,4-bis(N-hexadecyl-N,N-dimethylammonium)butane dibromide/1,2-dimyristoyl-sn-glycero-3-phosphocholine liposomes, only resulting in DNA condensation when X(SR-1) > 0.50. Condensation of DNA in turn seems to be required for efficient transfection.
authors.affiliation: Helsinki Biophysics and Biomembrane Group, Institute of Biomedicine/Biochemistry, University of Helsinki, Finland.
authors.forename: Samppa J
authors.initials: SJ
authors.lastname: Ryhänen
authors.forename: Matti J
authors.initials: MJ
authors.lastname: Säily
authors.forename: Tommi
authors.initials: T
authors.lastname: Paukku
authors.forename: Stefano
authors.initials: S
authors.lastname: Borocci
authors.forename: Giovanna
authors.initials: G
authors.lastname: Mancini
authors.forename: Juha M
authors.initials: JM
authors.lastname: Holopainen
authors.forename: Paavo K J
authors.initials: PK
authors.lastname: Kinnunen
mesh_terms: D000818:Animals; D019556:COS Cells / Q000737:chemistry / Q000187:drug effects; D002412:Cations; D002417:Cattle; D004247:DNA / Q000737:chemistry* / Q000633:toxicity; D004337:Drug Carriers; D008081:Liposomes / Q000737:chemistry* / Q000633:toxicity; D010713:Phosphatidylcholines / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry* / Q000633:toxicity; D055672:Static Electricity; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry; D013696:Temperature; D014162:Transfection / Q000295:instrumentation / Q000379:methods*
chemical_list: C440188:2,3-dimethoxy-1,4-bis(N-hexadecyl-N,N-dimethylammonium)butane; D002412:Cations; D004337:Drug Carriers; D008081:Liposomes; D010713:Phosphatidylcholines; D000644:Quaternary Ammonium Compounds; D013501:Surface-Active Agents; D004247:DNA; C427203:calf thymus DNA