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

Europium-doped gadolinium oxide (GdO:Eu) 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, GdO:Eu NPs with various Eu doping concentrations were prepared by the facile and general technique of laser ablation in liquid (LAL). The influence of Eu-doping concentration on fluorescence properties and longitudinal relaxivity were investigated. The optimum Eu-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 GdO:Eu NPs prepared by LAL are promising candidates for highly efficient FI and MRI dual-modal contrast agents.