Controllable synthesis of Gd2O(CO3)2·H2O@silica–FITC nanoparticles with size-dependent optical and magnetic resonance imaging properties

Abstract

Gadolinium carbonate (Gd₂O(CO₃)₂·H₂O) nanoparticles (NPs) with different diameters (from 280 nm to 10 nm) were obtained through a simple hydrothermal process by adding different volumes of glycerol. These Gd₂O(CO₃)₂·H₂O NPs were further coated with a thin layer of silica containing fluorescent dye (fluorescein isothiocyanate, FITC), and the possibility of using these NPs for optical imaging was demonstrated. In addition, due to the presence of Gd³⁺ ions on the surface of the NPs, magnetic resonance imaging (MRI) of Gd₂O(CO₃)₂·H₂O NPs with different diameters was also reported in detail. Considering the effect of NPs' size on their biocompatibility and MRI properties, our research results indicated that the Gd₂O(CO₃)₂·H₂O NPs of 50 nm showed the highest cytotoxicity and the maximum uptake by cells, and the MRI properties of Gd₂O(CO₃)₂·H₂O@silica–FITC NPs are also size-dependent. Therefore, these NPs exhibit bifunctionality for both optical imaging and MRI, making them potentially applicable in the biomedical field.