Evaluation of physicochemical and biocompatibility characteristics of gadolinium oxide nanoparticles as magnetic resonance imaging contrast agents

The attractive properties of gadolinium-based nanoparticles as a positive contrast agent for magnetic resonance imaging (MRI) have piqued the interest of both researchers and clinicians. Nonetheless, due to the biotoxicity of gadolinium (III) ions' free radicals, there is a need to address this issue. Therefore, this research aimed to develop and evaluate of physicochemical and biocompatibility characteristics of gadolinium oxide nanoparticles (Gd2O3- NPs) as MRI contrast agents. Whereby, the Gd2O3-NPs were synthesized via sol-gel method at various annealing temperatures of (500 degrees C-1100 degrees C). The results showed that the Gd2O3-NPs annealed at a temperature of 1000 degrees C exhibited prominent physicochemical properties in comparison to other annealing temperatures such as high saturation magnetization, colloidal stability with a highly positive surface charge, high crystallinity percentage, high weight percentage of gadolinium Gd and small energy band gap of 4 eV. Moreover, during the heating process, the complete decomposition of gadolinium hydroxide (Gd(OH)3) resulted in a significant increase in signal intensity in T1-weighted MRI images. The enhanced signal intensity in MRI is caused by structural changes in tissues or the contrast agent, which affect their interaction with the magnetic field, leading to the increased signal due to molecular conformation, aggregation, and mobility influencing T1 relaxation properties. Further-more, the biocompatibility of Gd2O3-NPs synthesized at 1000 degrees C was assessed through MTT assay tests on Hep G2 cells, which demonstrated good biocompatibility without any cytotoxic effects. The sol-gel technique shows promise in synthesizing Gd2O3-NPs with remarkable properties for various applications, including MRI contrast agents, by controlling annealing temperature.