title: Interfacial pressure and phospholipid density at emulsion droplet interface using fluorescence microscopy.
abstract: Phospholipids are widely used to stabilize oil in water micron size emulsion droplets; the interfacial phospholipid density and tension of such droplets are difficult to estimate. In the present paper, we describe a simple approach by which the measurement of a micron size oil droplet interface fluorescence intensity provides directly both the interfacial phospholipid density and the interfacial tension. This method relies on two prior calibration steps: (i) the quantitative variation of the interfacial tension with fluorescence intensity at droplets interface through micro-manipulation techniques; (ii) the variation of interfacial tension with phospholipid density through monolayer isotherm. Here, we show the validity of this approach with the example of micron size oil droplets stabilized with a phosphatidylcholine phospholipid, in aqueous buffer.
authors.affiliation: Laboratoire de Physique Statistique, UMR CNRS 8550 associée aux universités Paris 6 et Paris 7, École Normale Supérieure, 24 rue Lhomond, 75005 Paris, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Delacotte
authors.affiliation: Laboratoire de Physique Statistique, UMR CNRS 8550 associée aux universités Paris 6 et Paris 7, École Normale Supérieure, 24 rue Lhomond, 75005 Paris, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Gourier
authors.affiliation: Laboratoire de Physique Statistique, UMR CNRS 8550 associée aux universités Paris 6 et Paris 7, École Normale Supérieure, 24 rue Lhomond, 75005 Paris, France. Electronic address: pincet@lps.ens.fr.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Pincet
mesh_terms: D002138:Calibration; D004655:Emulsions; D066292:Lipid Droplets / Q000737:chemistry*; D008856:Microscopy, Fluorescence / Q000379:methods*; D010743:Phospholipids / Q000737:chemistry*; D013500:Surface Tension; D013696:Temperature
chemical_list: D004655:Emulsions; D010743:Phospholipids
keywords: Emulsion; Fluorescence microscopy; Interfacial tension; Monolayer isotherm; Oil droplet; Phospholipids