Effect of Eu doping concentration on fluorescence and magnetic resonance imaging properties of Gd2O3:Eu3+ nanoparticles used as dual-modal contrast agent.

Europium-doped gadolinium oxide (Gd2O3:Eu3+) nanoparticles (NPs) with favorable properties for use in fluorescence imaging (FI) and magnetic resonance imaging (MRI) dual-modal contrast agent has attracted intense attention in biomedical applications. However, limited information is available on balancing FI and MRI by adjusting doping concentrations. In this study, Gd2O3:Eu3+ NPs with various Eu3+ doping concentrations were prepared by the facile and general technique of laser ablation in liquid (LAL). The influence of Eu3+-doping concentration on fluorescence properties and longitudinal relaxivity were investigated. The optimum Eu3+-doping concentration with both high fluorescence properties and longitudinal relaxivity was determined to be 5%. The characterization of the structure, morphology, and composition shows that these NPs possess good crystallinity and excellent dispersibility. These results show that Gd2O3:Eu3+ NPs prepared by LAL are promising candidates for highly efficient FI and MRI dual-modal contrast agents.