title: Fusogenic supramolecular vesicle systems induced by metal ion binding to amphiphilic ligands.
abstract: The incorporation of lipophilic ligands into the bilayer membrane of vesicles offers the possibility to induce, upon binding of suitable metal ions, a variety of processes, in particular vesicle aggregation and fusion and generation of vesicle arrays, under the control of specific metal-ligand recognition events. Synthetic bipyridine lipoligands Bn bearing a bipyridine unit as head group were prepared and incorporated into large unilamellar vesicles. The addition of Ni2+ or Co2+ metal ions led to the formation of complexes MBn and MBn2 followed by spontaneous fusion to generate giant multilamellar vesicles. The metal ion complexation was followed by UV spectroscopy and the progressive fusion could be visualized by optical dark-field and fluorescence microscopies. Vesicle fusion occurred without leakage of the aqueous compartments and resulted in the formation of multilamellar giant vesicles because of the stacking of the lipoligands Bn. The fusion process required a long enough oligoethylene glycol spacer and a minimal concentration of lipoligand within the vesicle membrane. Metallosupramolecular systems such as the present one offer an attractive way to induce selective intervesicular processes, such as vesicle fusion, under the control of molecular recognition between specific metal ions and lipoligands incorporated in the bilayer membrane. They provide an approach to the design of artificial "tissue-mimetics" through the generation of polyvesicular arrays of defined architecture and to the control of their functional properties.
authors.affiliation: Laboratoire de Chimie des Interactions Moléculaires and Laboratoire de Physique de la Matière Condensée, Collège de France, 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France.
authors.forename: Antoine
authors.initials: A
authors.lastname: Richard
authors.forename: Valérie
authors.initials: V
authors.lastname: Marchi-Artzner
authors.forename: Marie-Noëlle
authors.initials: MN
authors.lastname: Lalloz
authors.forename: Marie-Josèphe
authors.initials: MJ
authors.lastname: Brienne
authors.forename: Franck
authors.initials: F
authors.lastname: Artzner
authors.forename: Thaddée
authors.initials: T
authors.lastname: Gulik-Krzywicki
authors.forename: Marie-Alice
authors.initials: MA
authors.lastname: Guedeau-Boudeville
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Lehn
mesh_terms: D002152:Calorimetry, Differential Scanning; D002412:Cations; D008024:Ligands; D008027:Light; D008051:Lipid Bilayers; D009682:Magnetic Resonance Spectroscopy; D008670:Metals / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D012542:Scattering, Radiation; D013056:Spectrophotometry, Ultraviolet
chemical_list: D002412:Cations; D008024:Ligands; D008051:Lipid Bilayers; D008670:Metals