We report a general and facile approach for the fabrication of a new class of near monodisperse hybrid nanoparticles via RAFT polymerization and self-assembly in water. Furthermore, we combine a fluorescent inorganic silica core with a biocompatible polymer shell and a terminal unit susceptible to facile conjugations via click chemistry. A tailoring of the weight fractions of both components allows a tuning of the size of the formed aggregates. Fluorescent properties and the crosslinking into an organic-inorganic hybrid network are realized by copolymerizing a dye-functionalized monomer 1-pyrenebutyl acrylate and a trimethoxysilane-carrying one, (3-acryloxypropyl)- trimethoxysilane. The potential of these stabilized and fluorescent nanoparticles as biocompatible carriers for intracellular delivery is demonstrated via in vitro experiments on lung cancer cells.