title: Detection of low quantum yield fluorophores and improved imaging times using metallic nanoparticles.
abstract: The behavior of a fluorophore near a gold nanoparticle is rationalized by a theoretical description of the parameters that modify the fluorescence emission: nanoparticle-fluorophore distance, fluorescence quantum yield (φ(0)), and fluorophore absorption and emission spectra, to find optimum conditions for designing fluorophore-nanoparticle probes. The theoretical maximum gain in brightness of the nanoparticle-fluorophore system with respect to the isolated molecule increases almost inversely proportional to φ(0). The brightness enhancement in imaging experiments in vitro was assessed by using Au-SiO(2) core-shell nanoparticles deposited on glass. A ~13-fold emission brightness enhancement for weakly fluorescent molecules was observed. A significant increase in fluorophore photostability, rendering longer imaging times, was obtained for fluorophores interacting with gold nanoparticles incorporated by endocytosis in cells. Our results illustrate a way to increase imaging times and to study molecules in the vicinity of a metallic nanoparticle after photobleaching of background fluorescence.
authors.affiliation: Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina.
authors.forename: Laura C
authors.initials: LC
authors.lastname: Estrada
authors.forename: M Julia
authors.initials: MJ
authors.lastname: Roberti
authors.forename: Sabrina
authors.initials: S
authors.lastname: Simoncelli
authors.forename: Valeria
authors.initials: V
authors.lastname: Levi
authors.forename: Pedro F
authors.initials: PF
authors.lastname: Aramendía
authors.forename: Oscar E
authors.initials: OE
authors.lastname: Martínez
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D005456:Fluorescent Dyes / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D008547:Melanophores / Q000166:cytology; D053768:Metal Nanoparticles / Q000737:chemistry*; D008856:Microscopy, Fluorescence / Q000379:methods*; D012822:Silicon Dioxide / Q000737:chemistry; D014982:Xenopus laevis
chemical_list: D005456:Fluorescent Dyes; D006046:Gold; D012822:Silicon Dioxide