title: Encapsulation of magnetic and fluorescent nanoparticles in emulsion droplets.
abstract: Oils containing both fluorescent semiconductor and magnetic oxide nanoparticles are used to produce oil in water emulsions. This technique produces oil droplets with homogeneous fluorescence and high magnetic nanoparticle concentrations. The optical properties of the oil droplets are studied as a function of the droplet sizes for various concentrations of fluorescent and magnetic nanoparticles. For all concentrations tested, we find a linear variation of the droplet fluorescent intensity as a function of the droplet volume. For a given size and a given quantum dot (QD) concentration, the droplet fluorescence intensity drops sharply as a function of the magnetic nanoparticle concentration. We show that this decrease is due mainly to the strong absorption cross section of the magnetic nanoparticles and to a lesser extent to the dynamic and static quenching of the QD fluorescence. The role of the iron oxide nanoparticle localization in the droplet (surface versus volume) is also discussed.
authors.affiliation: Laboratoire colloïdes et matériaux divisés, CNRS UMR 7612, ESPCI, 10 rue Vauquelin, 75231 Paris, France.
authors.forename: Swapan K
authors.initials: SK
authors.lastname: Mandal
authors.forename: Nicolas
authors.initials: N
authors.lastname: Lequeux
authors.forename: Benjamin
authors.initials: B
authors.lastname: Rotenberg
authors.forename: Marc
authors.initials: M
authors.lastname: Tramier
authors.forename: Jacques
authors.initials: J
authors.lastname: Fattaccioli
authors.forename: Jerome
authors.initials: J
authors.lastname: Bibette
authors.forename: Benoit
authors.initials: B
authors.lastname: Dubertret
mesh_terms: D000327:Adsorption; D004655:Emulsions / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D005453:Fluorescence; D008280:Magnetics; D008856:Microscopy, Fluorescence; D049329:Nanostructures; D036103:Nanotechnology; D009821:Oils / Q000737:chemistry*; D010316:Particle Size; D045663:Quantum Dots; D013499:Surface Properties; D013997:Time Factors
chemical_list: D004655:Emulsions; D005290:Ferric Compounds; D009821:Oils; C000499:ferric oxide