Fabrication of fluorescent microparticles by doping water-soluble CdTe nanocrystals into calcium carbonate for monitoring intracellular uptake

3-Mercaptopropyl acid (MPA) capped CdTe quantum dots (QDs) were embedded into CaCO 3 microparticles with a size of 1.4–4.4 μm by addition of the QDs into Ca(NO 3 ) 2 solution during a mineralization process. Compared to the parent QDs, about 1/7–1/3 photoluminescence efficiency of the embedded QDs was preserved, enabling the CaCO 3 (CdTe) particles visible under UV irradiation. The structure and morphology of the CaCO 3 (CdTe) particles were characterized by X-ray diffraction (XRD), UV–vis spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM). Protected by the CaCO 3 particles, the QDs in the composites were more stable against long term storage, UV irradiation and cell culture medium containing serum. The CaCO 3 (CdTe) particles could be internalized into live cells, human liver cancer cells (HepG2), for example, and most of which distributed in the lysosomes as revealed by confocal microscopy. Also the CaCO 3 (CdTe) particles had low cytotoxicity in comparison with the parent CdTe QDs.