Core–shell Fe3O4@NaLuF4:Yb,Er/Tm nanostructure for MRI, CT and upconversion luminescence tri-modality imaging

Core–shell Fe3O4@NaLuF4:Yb,Er/Tm nanostructure (MUCNP) with multifunctional properties has been developed using a step-wise synthetic method. The successful fabrication of MUCNP has been confirmed by transmission electron microscopy, powder X-ray diffraction, energy-dispersive X-ray analysis and X-ray photoelectron spectroscopy. The MUCNP exhibits superparamagnetic property with saturation magnetization of 15 emu g−1, and T2-enhanced magnetic resonance (MR) effect with an r2 value of 21.63 s−1 mM−1 at 0.5 T, resulting from the Fe3O4 cores. Moreover, the NaLuF4-based MUCNP provides excellent X-ray attenuation and upconversion luminescence (UCL) emission under excitation at 980 nm. In vivo MR, computed tomography (CT) and UCL images of tumor-bearing mice show that the MUCNP can be successfully used in multimodal imaging. In vitro tests reveal that the MUCNP is non-cytotoxic. These results suggest that the developed MUCNP could be served as an MR, CT and UCL probe for tri-modality imaging.