title: Transparent plasmonic nanocontainers protect organic fluorophores against photobleaching.
abstract: Numerous research efforts are investigating the possibility of using light interactions with metallic nanoparticles to improve the fluorescence properties of nearby molecules. Few investigations have considered the encapsulation of molecules in metallic nanocavities. In this paper, we present the optical properties of new hybrid nanoparticles consisting of gold nanoshells and fluorescent organic dyes in their liquid cores. Microspectroscopy on single nanoparticle demonstrates that the extinction spectra are in good agreement with Mie's theory. Finite difference time domain (FDTD) calculations reveal that excitation and emission radiations are efficiently transmitted through the thin gold nanoshells. Thus, they can be considered as transparent plasmonic nanocontainers for photoactive cores. In agreement with FDTD calculations, measurements show that fluorophores encapsulated in gold nanoshells keep their brightness, but they show fluorescence lifetimes 1 order of magnitude shorter. As a salient consequence, the photoresistance of encapsulated organic dyes is also improved by an order of magnitude. This unusual ultraviolet photoresistance results from the reduced probability of triplet-singlet conversion that eventually exposes dyes to singlet oxygen photodegradation.
authors.affiliation: Laboratoire Interdisciplinaire de Physique CNRS UMR 5588, Université Grenoble 1, Grenoble, F-38402, France.
authors.forename: Soraya
authors.initials: S
authors.lastname: Zaiba
authors.forename: Fréderic
authors.initials: F
authors.lastname: Lerouge
authors.forename: Ana-Maria
authors.initials: AM
authors.lastname: Gabudean
authors.forename: Monica
authors.initials: M
authors.lastname: Focsan
authors.forename: Jean
authors.initials: J
authors.lastname: Lermé
authors.forename: Thibault
authors.initials: T
authors.lastname: Gallavardin
authors.forename: Olivier
authors.initials: O
authors.lastname: Maury
authors.forename: Chantal
authors.initials: C
authors.lastname: Andraud
authors.forename: Stéphane
authors.initials: S
authors.lastname: Parola
authors.forename: Patrice L
authors.initials: PL
authors.lastname: Baldeck
mesh_terms: D000818:Animals; D002417:Cattle; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D008027:Light; D053768:Metal Nanoparticles / Q000737:chemistry; D049329:Nanostructures / Q000737:chemistry; D036103:Nanotechnology / Q000379:methods*; D009930:Organic Chemicals / Q000737:chemistry*; D038761:Photobleaching; D012235:Rhodamines / Q000737:chemistry; D012710:Serum Albumin, Bovine / Q000737:chemistry; D020349:Surface Plasmon Resonance; D013997:Time Factors; D014466:Ultraviolet Rays
chemical_list: D005456:Fluorescent Dyes; D009930:Organic Chemicals; D012235:Rhodamines; D012710:Serum Albumin, Bovine; D006046:Gold