We report the synthesis of luminescent carbon nanoparticles (93 ± 50 nm) embedded with Cu2+. It was observed that at a relatively low concentration of Cu2+ (2.55 ppm), cervical cancer HeLa cells died due to apoptosis induced by the nanoparticles. Also, generation of reactive oxygen species in the cells, in the presence of the composite nanoparticles, has been attributed to their killing. The luminescence of the carbon nanoparticles was used for imaging of the cells.