A Magnetic Chameleon: Biocompatible Lanthanide Fluoride Nanoparticles with Magnetic Field Dependent Tunable Contrast Properties as a Versatile Contrast Agent for Low to Ultrahigh Field MRI and Optical Imaging in Biological Window

Silvanose Biju; Juan Gallo; M Bañobre-López; Bella B Manshian; Stefaan J Soenen; Uwe Himmelreich; Luce Vander Elst; Tatjana N Parac-Vogt

doi:10.1002/chem.201800283

A Magnetic Chameleon: Biocompatible Lanthanide Fluoride Nanoparticles with Magnetic Field Dependent Tunable Contrast Properties as a Versatile Contrast Agent for Low to Ultrahigh Field MRI and Optical Imaging in Biological Window

Chemistry. 2018 May 23;24(29):7388-7397. doi: 10.1002/chem.201800283. Epub 2018 Apr 26.

Authors

Silvanose Biju¹, Juan Gallo², M Bañobre-López², Bella B Manshian³, Stefaan J Soenen³, Uwe Himmelreich³, Luce Vander Elst⁴, Tatjana N Parac-Vogt¹

Affiliations

¹ Laboratory of Bioinorganic Chemistry, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001, Leuven, Belgium.
² Advanced (Magnetic) Theranostic Nanostructures Group, INL-International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga, 4715-330, Braga, Portugal.
³ Department of Imaging and Pathology, Biomedical NMR unit, MoSAIC, KU Leuven, Herestraat 49, 3000, Leuven, Belgium.
⁴ Department of General, Organic and Biomedical Chemistry, University of Mons, Place du Parc 23, 7000, Mons, Belgium.

PMID: 29575427
DOI: 10.1002/chem.201800283

Abstract

A novel type of multimodal, magnetic resonance imaging/optical imaging (MRI/OI) contrast agent was developed, based on core-shell lanthanide fluoride nanoparticles composed of a β-NaHoF4 core plus a β-NaGdF4:Yb³⁺ , Tm³⁺ shell with an average size of ∼24 nm. The biocompatibility of the particles was ensured by a surface modification with poly acrylic acid (PAA) and further functionalization with an affinity ligand, folic acid (FA). When excited using 980 nm near infrared (NIR) radiation, the contrast agent (CA) shows intense emission at 802 nm with lifetime of 791±3 μs, due to the transition ³ H₄ →³ H₆ of Tm³⁺ . Proton nuclear magnetic relaxation dispersion (¹ H-NMRD) studies and magnetic resonance (MR) phantom imaging showed that the newly synthesized nanoparticles, decorated with poly(acrylic acid) and folic acid on the surface (NP-PAA-FA), can act mainly as a T₁ -weighted contrast agent below 1.5 T, a T₁ /T₂ dual-weighted contrast agent at 3 T, and as highly efficient T₂ -weighted contrast agent at ultrahigh fields. In addition, NP-PAA-FA showed very low cytotoxicity and no detectable cellular damage up to a dose of 500 μg mL^-1 .

Keywords: T1/T2 dual-weighted MRI; magnetic resonance imaging; multimodal imaging; nanomaterial; upconversion.