Calcium-doped organosilicate nanoparticles for gene delivery are prepared by using a surfactant-mediated sol-gel synthesis. The enhanced uptake of these nanoparticles by osteoblast cells (see figure) makes them promising candidates for the transfection of bone cells. The complexes of Ca-SiO2 nanoparticles with DNA transfect bone cells effectively without inducing cytotoxicity in vitro.