US Patent 7875466 Fluorescent magnetic nanoparticles and process of preparation

This invention provides nanometer-sized fluorescent magnetic particles and processes of making them. The nanoparticle has a core particle comprising a magnetic material and a fluorescent material, and the particle size is less than about 1 micrometer. The nanoparticles can be coated with an inorganic or organic layer and can be surface-modified. The nanoparticles can be used in many biological assays.