title: In vivo excitation of nanoparticles using luminescent bacteria.
abstract: The lux operon derived from Photorhabdus luminescens incorporated into bacterial genomes, elicits the production of biological chemiluminescence typically centered on 490 nm. The light-producing bacteria are widely used for in vivo bioluminescence imaging. However, in living samples, a common difficulty is the presence of blue-green absorbers such as hemoglobin. Here we report a characterization of fluorescence by unbound excitation from luminescence, a phenomenon that exploits radiating luminescence to excite nearby fluorophores by epifluorescence. We show that photons from bioluminescent bacteria radiate over mesoscopic distances and induce a red-shifted fluorescent emission from appropriate fluorophores in a manner distinct from bioluminescence resonance energy transfer. Our results characterizing fluorescence by unbound excitation from luminescence, both in vitro and in vivo, demonstrate how the resulting blue-to-red wavelength shift is both necessary and sufficient to yield contrast enhancement revealing mesoscopic proximity of luminescent and fluorescent probes in the context of living biological tissues.
authors.affiliation: Plate-Forme d'Imagerie Dynamique, Imagopole, Institut Pasteur, 25-28 Rue du Docteur Roux, 75724 Paris cedex 15, France. joseph.dragavon@pasteur.fr
authors.forename: Joe
authors.initials: J
authors.lastname: Dragavon
authors.forename: Samantha
authors.initials: S
authors.lastname: Blazquez
authors.forename: Abdessalem
authors.initials: A
authors.lastname: Rekiki
authors.forename: Chelsea
authors.initials: C
authors.lastname: Samson
authors.forename: Ioanna
authors.initials: I
authors.lastname: Theodorou
authors.forename: Kelly L
authors.initials: KL
authors.lastname: Rogers
authors.forename: Régis
authors.initials: R
authors.lastname: Tournebize
authors.forename: Spencer L
authors.initials: SL
authors.lastname: Shorte
mesh_terms: D000818:Animals; D004926:Escherichia coli; D005260:Female; D005453:Fluorescence; D049449:Luminescence; D049408:Luminescent Agents / Q000378:metabolism*; D008163:Luminescent Measurements; D051379:Mice; D008807:Mice, Inbred BALB C; D057054:Molecular Imaging / Q000379:methods*; D053758:Nanoparticles / Q000737:chemistry*; D045663:Quantum Dots; D013211:Staphylococcus aureus
chemical_list: D049408:Luminescent Agents