title: Fluorescent and highly stable unimodal DMPC based unilamellar vesicles formed by spontaneous curvature.
abstract: The formation of uniform and highly stable unilamellar vesicles (ULVs) and the theory behind it are ongoing tasks within the vesicle community. Herein, we report the formation of highly stable, fluorescent, and unimodal 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) based ULVs with an average size of ~100 nm, as determined by cryogenic transmission electron microscopy (cryo-TEM) and dynamic light scattering (DLS). The ULVs are formed by mixing a two-component powder mixture or mixed lipid film of DMPC and 5 mol % of a novel amphiphilic carbenium salt, sodium 2-didecylamino-6,10-bis(N-methyltaruino)-4,8,12-trioxatriangulenium (Na-DSA) in aqueous solution when subjected to shaking. We propose that the high stability and the unimodal size distribution of the 5% DSA ULVs confirmed by DLS studies are a product of spontaneous curvature. UV-vis absorption/emission studies reveal that the structure of DSA promotes a strong interaction between the DMPC and the DSA to take place due to the complementary charge distribution of the DSA and DMPC head groups. The strong interaction may introduce an asymmetric amphiphile composition in the inner and outer leaflet of the bilayer which drives the spontaneous curvature.
authors.affiliation: Nano-Science Center & Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark.
authors.forename: Dong
authors.initials: D
authors.lastname: Shi
authors.forename: George
authors.initials: G
authors.lastname: Sfintes
authors.forename: Bo W
authors.initials: BW
authors.lastname: Laursen
authors.forename: Jens B
authors.initials: JB
authors.lastname: Simonsen
mesh_terms: D020285:Cryoelectron Microscopy; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry*; D004337:Drug Carriers / Q000737:chemistry*; D005453:Fluorescence; D008027:Light; D011721:Pyrenes / Q000737:chemistry*; D012542:Scattering, Radiation; D013501:Surface-Active Agents / Q000737:chemistry*; D013696:Temperature; D053835:Unilamellar Liposomes / Q000737:chemistry*
chemical_list: D004337:Drug Carriers; D011721:Pyrenes; D013501:Surface-Active Agents; D053835:Unilamellar Liposomes; D004134:Dimyristoylphosphatidylcholine