Gadolinium Labeled Glycosylated Nanomagnetic Particles as Metabolic Contrast Agents in Molecular Magnetic Resonance Imaging

Abstract

Abstract-Difficulties in the use, preparation, and cost of radioactively-labeled glycosylated compounds led us to this research and development study of a new gadolinium-labeled glucose compounds that do not have a radioactive half-life or difficulties in its synthesis and utilization. Despite its good resolution, Magnetic Resonance Imaging (MRI) has low sensitivity, therefor, using MRI contrast agents, such as GD-DTPA (Magnevist) will improve tissue discrimination in MRI images.The purpose of this study is the synthesis and physicochemical characterization of glycosylated gadolinium as metabolic contrast agent for molecular MRI (mMRI). In-vitro T1 relaxivity measurement and signal intensity of the glycosylated compounds has been also performed in comparison with magnevist ( GD-DTPA).Based on the structure of the 2-fluoro-2-deoxy-D-glucose molecule (FDG), first compound consisting of D-glucose conjugated to a well-known chelator, diethylenetriamine pentaacetic acid (DTPA), was syntheside , labeled with Gd to achieve Gd-DTPA-DG, another comound consisting of gadolinium oxide-based nanoparticle coating of diethyleneglycol conjugated with D-glucose via N,N-carbonyldiimidazole (CDI) mediate reaction, to achieve Gd-DEG-DG, and characterized by various analytical technique, utilizes dynamic light scattering (DLS) to determine the size distribution. The nanoparticle size and morphology were using high resolution transmission electron microscopy (HTEM). In our study, the Gd-DTPA-DG were well defined nanoparticle with size 40 nm in diameter TEM images. While Gd-DEG-DG were 10 nm . The mean hydrodynamic diameter of nanoparticles, as measured by DLS, were 300 nm and 70 nm for GD-DTPA-DG and GD-DEG-DG, respectively.The synthesized GD-DTPA-DG and GD-DEG-DG were shown higher relaxometery rates in vitro relative to magnevist. GD-DEG-DG and GD-DTPA-DG demonstrated shorter T1 than GD-DTPA at the same conectration.