A novel class of fluorescent/superparamagnetic bifunctional nanoparticles was synthesized via the reverse microemulsion technique.These nanoparticles were studied with transmission electron microscopy(TEM) and SQUID microscopy.The results show that these nanoparticles have a typical diameter of 40 nm and a saturated magnetic moment of 1.9 emu/g at room temperature.The experiment results also show that these nanoparticles exhibit a strong excitonic photoluminescence.Then,these bifunctional nanoparticles were modified with vancomycin for binding.The results show that these vancomycin modified nanoparticles can capture selectively bacterias.