title: A step beyond BRET: Fluorescence by Unbound Excitation from Luminescence (FUEL).
abstract: Fluorescence by Unbound Excitation from Luminescence (FUEL) is a radiative excitation-emission process that produces increased signal and contrast enhancement in vitro and in vivo. FUEL shares many of the same underlying principles as Bioluminescence Resonance Energy Transfer (BRET), yet greatly differs in the acceptable working distances between the luminescent source and the fluorescent entity. While BRET is effectively limited to a maximum of 2 times the Förster radius, commonly less than 14 nm, FUEL can occur at distances up to µm or even cm in the absence of an optical absorber. Here we expand upon the foundation and applicability of FUEL by reviewing the relevant principles behind the phenomenon and demonstrate its compatibility with a wide variety of fluorophores and fluorescent nanoparticles. Further, the utility of antibody-targeted FUEL is explored. The examples shown here provide evidence that FUEL can be utilized for applications where BRET is not possible, filling the spatial void that exists between BRET and traditional whole animal imaging.
authors.affiliation: Plate-Forme d'Imagerie Dynamique, Imagopole, Institut Pasteur; joseph.dragavon@pasteur.fr.
authors.forename: Joseph
authors.initials: J
authors.lastname: Dragavon
authors.affiliation: Department of Radiation Oncology, Stanford School of Medicine.
authors.forename: Carolyn
authors.initials: C
authors.lastname: Sinow
authors.affiliation: Plate-Forme d'Imagerie Dynamique, Imagopole, Institut Pasteur.
authors.forename: Alexandra D
authors.initials: AD
authors.lastname: Holland
authors.affiliation: Plate-Forme d'Imagerie Dynamique, Imagopole, Institut Pasteur.
authors.forename: Abdessalem
authors.initials: A
authors.lastname: Rekiki
authors.affiliation: Service Hospitalier Frédéric Joliot, Institut d'Imagerie Biomédicale.
authors.forename: Ioanna
authors.initials: I
authors.lastname: Theodorou
authors.affiliation: Vanderbilt School of Medicine.
authors.forename: Chelsea
authors.initials: C
authors.lastname: Samson
authors.affiliation: Plate-Forme d'Imagerie Dynamique, Imagopole, Institut Pasteur.
authors.forename: Samantha
authors.initials: S
authors.lastname: Blazquez
authors.affiliation: The Walter & Eliza Hall Institute of Medical Research.
authors.forename: Kelly L
authors.initials: KL
authors.lastname: Rogers
authors.affiliation: Plate-Forme d'Imagerie Dynamique, Imagopole, Institut Pasteur; Unité INSERM U786, Institut Pasteur; Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur.
authors.forename: Régis
authors.initials: R
authors.lastname: Tournebize
authors.affiliation: Plate-Forme d'Imagerie Dynamique, Imagopole, Institut Pasteur; sshorte@pasteur.fr.
authors.forename: Spencer L
authors.initials: SL
authors.lastname: Shorte
mesh_terms: D004926:Escherichia coli / Q000737:chemistry; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D005456:Fluorescent Dyes / Q000737:chemistry; D007711:Klebsiella pneumoniae / Q000737:chemistry; D049453:Luciferases, Bacterial / Q000737:chemistry; D008163:Luminescent Measurements / Q000379:methods*; D053758:Nanoparticles / Q000737:chemistry; D010776:Photobacterium / Q000737:chemistry / Q000201:enzymology; D045663:Quantum Dots
chemical_list: D005456:Fluorescent Dyes; D049453:Luciferases, Bacterial