title: Selective Electrochemical Bleaching of the Outer Leaflet of Fluorescently Labeled Giant Liposomes.
abstract: Electrochemistry and confocal fluorescence microscopy were successfully combined to selectively bleach and monitor the fluorescence of NBD (7-nitrobenz-2-oxa-1,3-diazole)-labeled phospholipids of giant liposomes. Three types of giant unilamellar vesicles have been investigated, the fluorescent phospholipids being localized either mainly on their outer-, inner-, or both inner/outer leaflets. We established that only the fluorescent lipids incorporated in the outer leaflet of the vesicles underwent electrochemical bleaching upon reduction. The relative fluorescence intensity decay was quantified all along the electrochemical extinction through an original fluorescence loss in electrobleaching (FLIE) assay. As expected, the reorganization of the fluorescent phospholipids followed diffusion-driven dynamics. This was also evidenced by comparison with fluorescence loss in photobleaching (FLIP) and the corresponding numerical model. The value of the lateral diffusion coefficient of phospholipids was found to be similar to that obtained by other methods reported in the literature. This versatile and selective bleaching procedure appears reliable to explore important biological and pharmacological issues.
authors.affiliation: Ecole normale supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Département de Chimie, PASTEUR, 24 rue Lhomond, 75005, Paris, France.
authors.forename: Ana Isabel
authors.initials: AI
authors.lastname: Perez Jimenez
authors.affiliation: Ecole normale supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Département de Chimie, PASTEUR, 24 rue Lhomond, 75005, Paris, France.
authors.forename: Lylian
authors.initials: L
authors.lastname: Challier
authors.affiliation: Ecole normale supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Département de Chimie, PASTEUR, 24 rue Lhomond, 75005, Paris, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Aït-Yahiatène
authors.affiliation: Ecole normale supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Département de Chimie, PASTEUR, 24 rue Lhomond, 75005, Paris, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Delacotte
authors.affiliation: Ecole normale supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Département de Chimie, PASTEUR, 24 rue Lhomond, 75005, Paris, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Labbé
authors.affiliation: Ecole normale supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Département de Chimie, PASTEUR, 24 rue Lhomond, 75005, Paris, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Buriez
mesh_terms: D055664:Electrochemical Techniques; D005456:Fluorescent Dyes / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008081:Liposomes / Q000737:chemistry*; D018613:Microscopy, Confocal; D010069:Oxadiazoles / Q000737:chemistry; D010743:Phospholipids / Q000737:chemistry; D038761:Photobleaching
chemical_list: C526864:7-nitrobenz-2-oxa-1,3-diazole; D005456:Fluorescent Dyes; D008081:Liposomes; D010069:Oxadiazoles; D010743:Phospholipids
keywords: confocal microscopy; diffusion of phospholipids.; electrochemistry; fluorescence; lipid vesicles