Bright and stable CdSe/CdS@SiO₂ nanoparticles suitable for long-term cell labeling.

We report on the synthesis of luminescent CdSe/CdS@SiO2 nanoparticles and their application to cell labeling. The main novelty of these nanoparticles is the use of newly developed "flash" CdSe/CdS quantum dots (QDs), which are obtained through a new fast and efficient synthesis method recently reported. These core-shell QDs are encapsulated in silica nanoparticles through a water-in-oil microemulsion process, resulting in CdSe/CdS@SiO2 nanoparticles with good morphology and controlled architecture. The main asset of these luminescent nanoparticles is their high photoluminescent quantum yield, which is equal to that of the original CdSe/CdS QDs and remains unchanged even after several months of storage in water. Thanks to the remarkable stability of their optical property in aqueous environment and to their low levels of toxicity, the high potential of these nanoparticles for long-term cell labeling is demonstrated.