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

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.