Synthesis of Gd₂O₃:Eu nanoplatelets for MRI and fluorescence imaging

We synthesized Gd₂O₃ and Gd₂O₃ doped by europium (Eu) (2% to 10%) nanoplatelets using the polyol chemical method. The synthesized nanoplatelets were characterized by X-ray diffraction (XRD), FESEM, TEM, and EDX techniques. The optical properties of the synthesized nanoplatelets were investigated by photoluminescence spectroscopy. We also studied the magnetic resonance imaging (MRI) contrast enhancement of T1 relaxivity using 3 T MRI. The XRD for Gd₂O₃ revealed a cubic crystalline structure. The XRD of Gd₂O₃:Eu³⁺ nanoplatelets were highly consistent with Gd₂O₃ indicating the total incorporation of the Eu³⁺ ions in the Gd₂O₃ matrix. The Eu doping of Gd₂O₃ produced red luminescence around 612 nm corresponding to the radiative transitions from the Eu-excited state ⁵D₀ to the ⁷F₂. The photoluminescence was maximal at 5% Eu doping concentration. The stimulated CIE chromaticity coordinates were also calculated. Judd-Ofelt analysis was used to obtain the radiative properties of the sample from the emission spectra. The MRI contrast enhancement due to Gd₂O₃ was compared to DOTAREM commercial contrast agent at similar concentration of gadolinium oxide and provided similar contrast enhancement. The incorporation of Eu, however, decreased the MRI contrast due to replacement of gadolinium by Eu.