Many types of fluorescent nanoparticles have been synthesized as alternatives to organic dyes in biochemistry. Magnetic beads also have a long history of biological applications. In this work we apply flame spray pyrolysis in order to engineer a novel type of particle that has both fluorescent and magnetic properties. The particles have magnetic cores of iron oxide and a fluorescent shell of europium ? doped gadolinium oxide (Eu:Gd2O3). Measurements on a Vibrating Sample Magnetometer showed an overall paramagnetic response behavior of the composite particles. Fluorescence spectroscopy showed fluorescent spectra typical for the Eu ion in a Gd2O3 host with a narrow emission peak centered near 615 nm. Our synthesis method provides a low-cost, high-rate synthesis that allows a wide range of biological applications of magnetic/fluorescent core/shell particles. We show an immunoassay using the magnetic and fluorescent properties of the particles.
