Preparation and properties of bifunctional Gd2O3/GQD composite nanoparticles*

Abstract Nanocomposites of graphene quantum dots (GQDs) modified gadolinium oxide (Gd2O3) particles were successfully synthesized. In addition, the effects of the amount of GQDs and the particle size of Gd2O3 on the properties of nanocomposites were investigated. The structures and properties of nanoparticles were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, photoluminescence spectrometry, and magnetic resonance imaging. The results show that the synthesized particles Gd2O3/GQD are spherical with a diameter of approximately 40 nm and have excellent fluorescence and magnetic property, and its relaxation rate (r1 = 25.18 (mmol/L)–1/s) is higher than that of the typical commercial contrast agents Gd-DTPA (r1 = 4.5 (mmol/L)–1/s). The fluorescence property of Gd2O3/GQD is optimized by varying the VGQDs:VGd2O3 ratio, and 1:1 ratio of VGQDs:VGd2O3 results in best fluorescence property. The large particles of Gd2O3 improve the relaxation property of nanocomposites. Therefore, the nanocomposites Gd2O3/GQD with magnetic and fluorescence characteristics can be used in biological imaging, drug targeting, and in-vivo diagnostic analysis.