Room temperature synthesis of water-dispersible Ln 3+ :CeF 3 (Ln = Nd, Tb) nanoparticles with different morphology as bimodal probes for fluorescence and CT imaging.

The singular properties of lanthanide-based inorganic nanoparticles (NPs) has raised the attention of the scientific community in biotechnological applications. In particular, those systems with two or more functionalities are especially interesting. In this work, an effective and commercially attractive procedure has been developed that renders uniform, water-dispersible Ln3+ :CeF3 (Ln = Tb, Nd) NPs with different shapes and size. The method consists of the homogeneous precipitation, in a mixture of polyol and water, of cations and anions using precursors that allow the controlled release of the latter. The advantages of the reported method are related to the absence of surfactants, dispersing agents or corrosive precursors as well as to the room temperature of the process. The obtained Tb:CeF3 NPs produce an intense emission after excitation through the Ce-Tb energy transfer band located in the UV spectral region, thus being potentially useful as phosphors for in-vitro imaging purposes. On the other hand, the synthesized Nd:CeF3 NPs are good candidates for in-vivo imaging because their excitation and emission wavelengths lie in the biological windows. Finally, the excellent X-ray attenuation efficacy of the Nd:CeF3 NPs is shown, which confers double functionality to this material as both luminescence bioprobe and contrast agent for X-ray computed-tomography.