Potential dual imaging nanoparticle: Gd2O3 nanoparticle.

Md Wasi Ahmad,Wenlong Xu,Gang Ho Lee,Ji Ae Park,Sung June Kim,Yongmin Chang,Ji Eun Bae,Tae Jeong Kim,Jong Su Baeck,Kwon Seok Chae

doi:10.1038/srep08549

Abstract

Gadolinium (Gd) is a unique and powerful element in chemistry and biomedicine which can be applied simultaneously to magnetic resonance imaging (MRI), X-ray computed tomography (CT), and neutron capture therapy for cancers. This multifunctionality can be maximized using gadolinium oxide (Gd2O3) nanoparticles (GNPs) because of the large amount of Gd per GNP, making both diagnosis and therapy (i.e., theragnosis) for cancers possible using only GNPs. In this study, the T1 MRI and CT dual imaging capability of GNPs is explored by synthesizing various iodine compound (IC) coated GNPs (IC-GNPs). All the IC-GNP samples showed stronger X-ray absorption and larger longitudinal water proton relaxivities (r1 = 26–38 s−1mM−1 and r2/r1 = 1.4–1.9) than the respective commercial contrast agents. In vivo T1 MR and CT images of mice were also acquired, supporting that the GNP is a potential dual imaging agent.

Highlights

Gadolinium (Gd) is a unique and powerful element in chemistry and biomedicine which can be applied simultaneously to magnetic resonance imaging (MRI), X-ray computed tomography (CT), and neutron capture therapy for cancers
The gadolinium oxide (Gd2O3) nanoparticle (GNP) seems to be special because of its diagnostic and therapeutic properties (Fig. 1)[11,27,28,29]. This multifunctionality arises from the high spin magnetic moment (s 5 7/2) of a trivalent Gd(III) (8S7/2), which is useful for magnetic resonance imaging (MRI)[30,31]; the very high X-ray attenuation coefficient of Gd [less than that of gold but higher than that of iodine (I) that is commercially used as a CT contrast agent in triiodinic molecular forms], which is useful for X-ray computed tomography (CT)[32,33,34,35]; and the huge thermal neutron capture cross-section of 157Gd (15.6% natural abundance) of 257,000 barns, which is useful for neutron capture therapy (NCT) for cancers[36,37]
Four commercial iodine contrast agents were used as surface coating ligands on GNPs to maximize the CT functionality of the nanoparticles because of the iodines in the iodine compound (IC), as well as to make them water-soluble and biocompatible

Summary

Introduction

Gadolinium (Gd) is a unique and powerful element in chemistry and biomedicine which can be applied simultaneously to magnetic resonance imaging (MRI), X-ray computed tomography (CT), and neutron capture therapy for cancers. The gadolinium oxide (Gd2O3) nanoparticle (GNP) seems to be special because of its diagnostic and therapeutic properties (Fig. 1)[11,27,28,29] This multifunctionality arises from the high spin magnetic moment (s 5 7/2) of a trivalent Gd(III) (8S7/2) (the largest value among the elements in the periodic table), which is useful for magnetic resonance imaging (MRI)[30,31]; the very high X-ray attenuation (or absorption) coefficient of Gd [less than that of gold but higher than that of iodine (I) that is commercially used as a CT contrast agent in triiodinic molecular forms], which is useful for X-ray computed tomography (CT)[32,33,34,35]; and the huge thermal neutron capture cross-section of 157Gd (15.6% natural abundance) of 257,000 barns (the largest value among the known stable radio-isotopes), which is useful for neutron capture therapy (NCT) for cancers[36,37]. To prove the potential of GNPs as a dual imaging agent, the water proton relaxivities, X-ray absorption, and in vitro cellular cytotoxicities were measured, and in vivo T1 MR and CT images of mice were acquired after intravenous injection

Methods

Results

Conclusion