Polyol-Made Luminescent and Superparamagnetic β-NaY(0.8)Eu(0.2)F(4)@γ-Fe(2)O(3) Core-Satellites Nanoparticles for Dual Magnetic Resonance and Optical Imaging

Red luminescent and superparamagnetic β-NaY(0.8)Eu(0.2)F(4)@γ-Fe(2)O(3) nanoparticles, made of a 70 nm-sized β-NaY(0.8)Eu(0.2)F(4) single crystal core decorated by a 10 nm-thick polycrystalline and discontinuous γ-Fe(2)O(3) shell, have been synthesized by the polyol process. Functionalized with citrate ligands they show a good colloidal stability in water making them valuable for dual magnetic resonance and optical imaging or image-guided therapy. They exhibit a relatively high transverse relaxivity r(2) = 42.3 mM(−1)·s(−1) in water at 37 °C, for an applied static magnetic field of 1.41 T, close to the field of 1.5 T applied in clinics, as they exhibit a red emission by two-photon excited fluorescence microscopy. Finally, when brought into contact with healthy human foreskin fibroblast cells (BJH), for doses as high as 50 µg·mL(−1) and incubation time as long as 72 h, they do not show evidence of any accurate cytotoxicity, highlighting their biomedical applicative potential.