New Class of Efficient T2 Magnetic Resonance Imaging Contrast Agent: Carbon-Coated Paramagnetic Dysprosium Oxide Nanoparticles
Department of Chemistry, Department of Nanoscience and Nanotechnology (DNN), College of Natural Sciences, Kyungpook National University (KNU), Taegu 41566, Korea
Division of RI-Convergence Research, Korea Institute of Radiological & Medical Sciences (KIRAMS), Seoul 01817, Korea
Department of Molecular Medicine and Medical & Biological Engineering, DNN, School of Medicine, KNU and Hospital, Taegu 41566, Korea
Department of Biology Education, DNN, Teachers’ College, KNU, Taegu 41566, Korea
Authors to whom correspondence should be addressed.
Pharmaceuticals 2020, 13(10), 312; https://doi.org/10.3390/ph13100312
Received: 20 August 2020 / Revised: 13 October 2020 / Accepted: 13 October 2020 / Published: 15 October 2020
(This article belongs to the Special Issue Next Generation of MRI Agents)
Nanoparticles are considered potential candidates for a new class of magnetic resonance imaging (MRI) contrast agents. Negative MRI contrast agents require high magnetic moments. However, if nanoparticles can exclusively induce transverse water proton spin relaxation with negligible induction of longitudinal water proton spin relaxation, they may provide negative contrast MR images despite having low magnetic moments, thus acting as an efficient T2 MRI contrast agent. In this study, carbon-coated paramagnetic dysprosium oxide ([email protected]) nanoparticles (core = DYO = DyxOy; shell = carbon) were synthesized to explore their potential as an efficient T2 MRI contrast agent at 3.0 T MR field. Since the core DYO nanoparticles have an appreciable (but not high) magnetic moment that arises from fast 4f-electrons of Dy(III) (6H15/2), the [email protected] nanoparticles exhibited an appreciable transverse water proton spin relaxivity (r2) with a negligible longitudinal water proton spin relaxivity (r1). Consequently, they acted as a very efficient T2 MRI contrast agent, as proven from negative contrast enhancements seen in the in vivo T2 MR images.