Abstract: CdTe@SiO₂ microspheres were synthesized by modified Stber method, and then CdTe@SiO₂@GdF₃fluorescence/magnetic resonance imaging dual functional microsphere with core/shell structure were prepared by direct precipitation method. Furthermore the structure, magnetic resonance imaging and fluorescence property were characterized by transmission electron microscope (TEM), energy dispersive Xray analysis (EDXA),  magnetic resonance imaging (MRI), Fourier transform infrared spectroscopy (FT-IR) and fluorescence spectrum. The experimental results show that the synthesized microsphere has obvious spherical core/shell structure, a large number of GdF3 dispersed well on the surface of silica in the form of small particles, and the particle sizes are 5—8 nm. Si,O and Gd elements can be detected on the surface of CdTe@SiO₂@GdF₃ microsphere, and Gd has been doped into the CdTe@SiO₂ materials. Compared with CdTe quantum dots, the fluorescence emission spectra of CdTe@SiO₂@GdF₃ microspheres have a red shift, but still have good fluorescence property. The relaxation parameter r₁ of CdTe@SiO₂@GdF₃ microspheres is 3.48 s^-1/(mmol·L^-1), so the synthesized CdTe@SiO2@GdF3 microspheres can be used for T₁weighted magnetic resonance imaging. When mass concentration of CdTe@SiO₂@GdF₃ is 200 μg/mL, the cell viability is still above 90%, indicating that the toxicity of the microphere on cells is weak.

Key words: CdTe quantum dot, gadolinium fluoride, fluorescence,  , magnetic resonance imaging