Spray pyrolysis synthesis of particles possessing magnetic and luminescent properties. Application of magnetic/luminescent particles in immunoassays

摘要

Many types of fluorescent nanoparticles have been investigated as alternatives to conventional organic dyes in biochemistry. In addition, magnetic beads are another type of particle that have a long history of biological applications. In this work we apply flame spray pyrolysis in order to engineer a novel type of nanoparticle that has both luminescent and magnetic properties. The particles have magnetic cores of iron oxide doped with cobalt and neodymium and luminescent shells of europium - doped gadolinium oxide (Eu:Gd_2O_3). Measurements by Vibrating Sample Magnetometry showed an overall paramagnetic response of these composite particles. Fluorescence spectroscopy showed spectra typical of the Eu ion in a Gd_2O_3 host - a narrow emission peak centered near 615 nm. Our synthesis method offers low-cost, high-rate synthesis allowing a wide range of biological applications of magnetic/fluorescent core/shell particles. We demonstrate an immunoassay using the magnetic and fluorescent properties of the particles for separation and detection purposes.