Issue 66, 2016

Multifunctional β-NaGdF4:Ln3+ (Ln = Yb, Er, Dy) nanoparticles with NIR to visible upconversion and high transverse relaxivity: a potential bimodal contrast agent for high-field MRI and optical imaging

Abstract

A novel series of active-core/active-shell upconverting nanoparticles (AC/AS-UCNPs) based on NaGdF4 doped with Yb3+/Er3+ in the core and Yb3+/Dy3+ in the shell having average particle size between 29.2 and 32.9 nm were synthesized. The UCNPs exhibit favorable properties for bimodal magnetic resonance imaging (MRI) and optical imaging (OI). Excitation of the UCNPs at 980 nm dispersed in water at room temperature resulted in intense green upconversion emission of Er3+. The proton nuclear magnetic relaxation dispersion (1H-NMRD) studies show very low longitudinal relaxivity (r1) values, which decreases with an increase of magnetic field. On the other hand, the transverse relaxivity (r2) values show an increasing trend with both increase in doping of Dy3+ as well as the increase in magnetic field reaching a maximum value of r2 = 70.07 s−1 mM−1 (per Ln3+ ion) for NaGdF4:Yb3+/Er3+ # NaYbF4:38.06% Dy3+ at 500 MHz and 310 K. Exhibiting such a high r2 value at high magnetic field and intense upconversion luminescence under 980 nm excitation makes these NPs exceptional candidates towards bioimaging applications.

Graphical abstract: Multifunctional β-NaGdF4:Ln3+ (Ln = Yb, Er, Dy) nanoparticles with NIR to visible upconversion and high transverse relaxivity: a potential bimodal contrast agent for high-field MRI and optical imaging

Supplementary files

Article information

Article type
Paper
Submitted
12 apr 2016
Accepted
18 jun 2016
First published
27 jun 2016

RSC Adv., 2016,6, 61443-61448

Multifunctional β-NaGdF4:Ln3+ (Ln = Yb, Er, Dy) nanoparticles with NIR to visible upconversion and high transverse relaxivity: a potential bimodal contrast agent for high-field MRI and optical imaging

S. Biju, M. Harris, L. V. Elst, M. Wolberg, C. Kirschhock and T. N. Parac-Vogt, RSC Adv., 2016, 6, 61443 DOI: 10.1039/C6RA09450C

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