Growth of lanthanide-doped LiGdF4 nanoparticles induced by LiLuF4 core as tri-modal imaging bioprobes

Multimodal imaging can compensate for the deficiencies and incorporate the advantages of individual imaging modalities . In this paper, we demonstrated the synthesis of core–shell nanocomposites LiLuF 4 @LiGdF 4 :Yb,Er/Tm constituted of tetragonal LiLuF 4 nanoparticles as core and Yb,Er/Tm-codoped LiGdF 4 as shell. LiLuF 4 @LiGdF 4 :Yb,Er/Tm nanoparticles display brighter upconversion luminescence (UCL) than NaGdF 4 :Yb,Er/Tm nanoparticles with the same size under continuous-wave excitation at 980 nm. The active shell layer of LiGdF 4 :Yb,Er/Tm not only provide the UCL center, but also serve as magnetic resonance (MR) imaging contrast agent. To further improve the UCL intensity, the inert LiGdF 4 shell was coated on the LiLuF 4 @LiGdF 4 :Yb,Er/Tm nanoparticles. Furthermore, LiLuF 4 @LiGdF 4 :Yb,Tm@LiGdF 4 nanoparticles have been successfully applied to UCL/X-ray computed tomography (CT)/MR tri-modal imaging on the modal of tumor-bearing mice.