Synthesized Gd2O3 nanoparticles as contrast agent

Abstract

Introduction: Gd (III) ion has been known to be the best metal ion in the periodic table that can be used as a T1 MRI contrast agent. Gadolinium have 7 unpaired electrons and these electrons can make magnetic area. No other metal ions possess unpaired electron more than this. CAs based on the element Gd are classified as “positive”, by opposition to “negative” CAs. Nowadays, Gd (III) chelates is prevailing in clinical use because it can be generally used for all organ. Around 35% of all MRI exams occur with contrast agents, and Gd (III) complexes are by far the most widely used contrast agents in clinical practice. The presence of superparamagnetic iron oxide particles in a tissue significantly changes the local magnetic field. Therefore, the optimal conditions to achieve 1H Larmor resonance are very sensitively affected. Suspensions of USPIO and SPIO typically express R2/R1 larger than 2. Physical properties of this magnetic element nanostructure have not studied so much yet. In this paper we have synthesized nanoparticles of Gadolinium Oxide in Polyol method and we try to compare it with commercial MRI contrast agent. On the other hand, there are reports about the effects of hyperthermia through the applying of strong magnetic fields on iron oxide superparamagnetism nanostructures. Later this property was used to treat cancer. Materials and Methods: We use Gd(NO3)3.6H2O, DEG, PVP 1.300.000 and NaOH that prepared by Sigma Merck to synthesized nanoparticles. We have verified this structure using Transmission electron microscopy (TEM), Dynamic light scattering (DLS) and X-ray crystallography (XRD) tests. Also we use Hyperthermia to calculate the temperature rise in magnetic field. Then we study magnetic properties of these nanoparticles with VSM and MRI images and compare it with two conventional contrast agents: Dotarem and Gadovist. Results: The DLS and TEM results show a diameter of 5 nm for the particles, with homogenous distributions among the solution. The XRD pattern show that we have crystal of Gd2O3. However, VSM results show that the anisotropy of this nanoparticles is 5.4 ×10-3 (J/m3) and a superparamagnetic loop, this value means we could have better relaxation time compared to Dotarem and Gadovist in magnetic area. By calculate the values we could find the relaxation time of our nanoparticles are 100 time smaller than commercial contrast agents. Hyperthermia shows 14ᵒ temperature rise in 0.15 T magnetic area that it could be used in cancer treatment. Conclusion: At the end of paper, we put the same concentration of Dotarem, Gadovist and nanoparticles in MRI image. By the results that calculate in VSM we guess that the contrast of nanoparticles must be better than commercial contrast agents. The results show that the highest contrast among these three structures refers to nanostructures. These results were obtained based on Hydrogens relaxation. This can be the base of using this nanoparticles as a MRI contrast agent in future.