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High Relaxivities and Strong Vascular Signal Enhancement for NaGdF 4 Nanoparticles Designed for Dual MR/Optical Imaging
Author(s) -
Naccache Rafik,
Chevallier Pascale,
Lagueux Jean,
Gossuin Yves,
Laurent Sophie,
Vander Elst Luce,
Chilian Cornelia,
Capobianco John A.,
Fortin MarcAndré
Publication year - 2013
Publication title -
advanced healthcare materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.288
H-Index - 90
eISSN - 2192-2659
pISSN - 2192-2640
DOI - 10.1002/adhm.201300060
Subject(s) - nanoparticle , materials science , analytical chemistry (journal) , biodistribution , x ray photoelectron spectroscopy , nuclear magnetic resonance , absorption (acoustics) , paramagnetism , sodium citrate , mri contrast agent , nuclear chemistry , chemistry , nanotechnology , medicine , biochemistry , physics , chromatography , quantum mechanics , pathology , in vitro , composite material
Near‐infrared (NIR)‐to‐NIR upconverting NaY(Gd)F 4 :Tm 3+ ,Yb 3+ paramagnetic nanoparticles (NPs) are efficiently detected by NIR imaging techniques. As they contain Gd 3+ ions, they also provide efficient “positive” contrast in magnetic resonance imaging (MRI). Water‐dispersible small (≈25 nm, “S‐”) and ultrasmall (<5 nm diam., “US‐”) NaY(Gd)F 4 :Tm 3+ ,Yb 3+ NPs are synthesized by thermal decomposition and capped with citrate. The surface of citrate‐coated US‐NPs shows sodium depletion and high Gd elemental ratios, as confirmed by a comparative X‐ray photoelectron spectroscopy (XPS)/neutron absorption analysis study. US‐NaGd 0.745 F 4 :Tm 0.005 ,Y b0.25 NPs have hydrodynamic diameters close to that measured by TEM, with the lowest relaxometric ratios ( r 2 / r 1 = 1.18) reported for NaGdF 4 nanoparticle suspensions ( r 1 = 3.37 mM −1 s −1 at 1.4 T and 37 °C). Strong relaxivity peaks in the range of 20 (0.47 T) ‐ 300 MHz (7.05 T) are revealed in nuclear magnetic resonance dispersion profiles, with high r 2 / r 1 ratios at increasing field strengths for S‐NPs. This indicates the superiority of US‐NPs over S‐NPs for achieving high positive contrast at clinical MRI field strengths. I.‐v. injected citrate‐coated US‐NPs evidence long blood retention times (>90 min) in mice. Biodistribution studies (48 h, 8 d) show elimination through the reticuloendothelial and urinary systems, similarly to other citrate‐capped US‐NP systems. In summary, upconverting NaY(Gd)F 4 :Tm 3+ ,Yb 3+ nanoparticles have promising luminescent, relaxometric and blood‐retention properties for dual MRI/optical imaging.