Red-emitting fluorescent organic@silicate core-shell nanoparticles for bio-imaging

Here we demonstrate that the encapsulation of crystal-state emitters in sol-gel matrices is an efficient way to produce bright nanotracers for bioimaging applications. We report the development of a family of fluorescent organic@silicate core-shell nanoparticles (NPs) containing an organic core surrounded by a silicate shell, with a high loading of dyes (30-40 wt%), prepared by an original spray-drying technique combining sol-gel chemistry and nanocrystallization. Four dyes were encapsulated within the silicate nanoparticles. The crystallinity of the organic core is discussed on the basis of characterization by electron microscopy and fluorescence spectroscopy. Bright, red-emitting core-shell NPs have been produced, which are promising for use in bio-imaging. Original core-shell nanoparticles featuring a fluorescent organic nanocrystalline core emitting in the red region are described.