Embedding Gd2O3 nanoparticles hydrothermally prepared in a Fe3O4 shell and surface modification with a dextrose bio capping agent

Abstract

The present work describes a multi-stage processing method for the hydrothermal synthesis of gadolinium oxide (Gd2O3) nanoparticles and subsequent surface modification with iron oxide (Fe3O4) and dextrose. To prepare gadolinium oxide nanoparticles, gadolinium chloride was reacted with sodium hydroxide, and the resulting precipitate was autoclaved. Subsequently, the product was calcined. Afterward, Gd2O3 nanoparticles were coated with a Fe3O4 nanolayer synthesized via coprecipitation, and the resulting core-shell nanocomposites were encapsulated in a dextrose capping agent for enhanced biocompatibility. The effect of various Gd2O3 synthesis parameters on particle size, structure, and magnetic properties was then investigated. These parameters included preliminary precipitation temperature (25, 90 °C) and stirring speed (400, 1000 rpm), hydrothermal temperature (150 and 180 °C) and pressure (5 and 10 bar), and final calcination temperature (600 and 1000 °C). For the investigation of nanocomposites, X-ray diffraction (XRD), scanning and transmission electron microscopy, dynamic laser scattering (DLS), Fourier-Transform infrared spectroscopy (FTIR), and magnetometry (VSM) techniques were used, while the viability of colloidal samples was determined using the MTT-assay method. The results indicated that increasing the steering speed and temperature of the precipitation process and raising the calcination temperature reduced the size of Gd2O3 nanoparticles. Autoclave dehydration had no discernible effect on Gd2O3 nanoparticles. TEM and SEM images confirmed the core/shell structure of Gd2O3/Fe3O4. The shell thickness of 74–95 nm core nanoparticles was in the range of 30–40 nm. With a saturation magnetization of 3.4 emu/g, the nanoparticles exhibited paramagnetic behavior. The 48-h MTT assay demonstrated excellent biocompatibility up to 285 μg solid concentrations containing 24.5 μg [Fe] and 91.2 μg [Gd], with viability remaining greater than 50% at 400 μg solid concentration.