title: Multifunctional rare-Earth vanadate nanoparticles: luminescent labels, oxidant sensors, and MRI contrast agents.
abstract: Collecting information on multiple pathophysiological parameters is essential for understanding complex pathologies, especially given the large interindividual variability. We report here multifunctional nanoparticles which are luminescent probes, oxidant sensors, and contrast agents in magnetic resonance imaging (MRI). Eu(3+) ions in an yttrium vanadate matrix have been demonstrated to emit strong, nonblinking, and stable luminescence. Time- and space-resolved optical oxidant detection is feasible after reversible photoreduction of Eu(3+) to Eu(2+) and reoxidation by oxidants, such as H2O2, leading to a modulation of the luminescence emission. The incorporation of paramagnetic Gd(3+) confers in addition proton relaxation enhancing properties to the system. We synthesized and characterized nanoparticles of either 5 or 30 nm diameter with compositions of GdVO4 and Gd0.6Eu0.4VO4. These particles retain the luminescence and oxidant detection properties of YVO4:Eu. Moreover, the proton relaxivity of GdVO4 and Gd0.6Eu0.4VO4 nanoparticles of 5 nm diameter is higher than that of the commercial Gd(3+) chelate compound Dotarem at 20 MHz. Nuclear magnetic resonance dispersion spectroscopy showed a relaxivity increase above 10 MHz. Complexometric titration indicated that rare-earth leaching is negligible. The 5 nm nanoparticles injected in mice were observed with MRI to concentrate in the liver and the bladder after 30 min. Thus, these multifunctional rare-earth vanadate nanoparticles pave the way for simultaneous optical and magnetic resonance detection, in particular, for in vivo localization evolution and reactive oxygen species detection in a broad range of physiological and pathophysiological conditions.
authors.affiliation: Laboratoire d'Optique et Biosciences, Ecole Polytechnique , CNRS UMR 7645-INSERM U696, 91128 Palaiseau Cedex, France.
authors.forename: Mouna
authors.initials: M
authors.lastname: Abdesselem
authors.forename: Markus
authors.initials: M
authors.lastname: Schoeffel
authors.forename: Isabelle
authors.initials: I
authors.lastname: Maurin
authors.forename: Rivo
authors.initials: R
authors.lastname: Ramodiharilafy
authors.forename: Gwennhael
authors.initials: G
authors.lastname: Autret
authors.forename: Olivier
authors.initials: O
authors.lastname: Clément
authors.forename: Pierre-Louis
authors.initials: PL
authors.lastname: Tharaux
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Boilot
authors.forename: Thierry
authors.initials: T
authors.lastname: Gacoin
authors.forename: Cedric
authors.initials: C
authors.lastname: Bouzigues
authors.forename: Antigoni
authors.initials: A
authors.lastname: Alexandrou
mesh_terms: D000818:Animals; D003287:Contrast Media / Q000737:chemistry*; D049449:Luminescence; D008279:Magnetic Resonance Imaging; D008674:Metals, Rare Earth / Q000737:chemistry*; D051379:Mice; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry*; D016877:Oxidants / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014639:Vanadium / Q000737:chemistry*
chemical_list: D003287:Contrast Media; D008674:Metals, Rare Earth; D016877:Oxidants; D014639:Vanadium
keywords: MRI; contrast agent; lanthanide nanoparticles; multifunctional probe; oxidant sensor