Development of liquid phase immunoassay system using magnetic nanoparticles

Biological immunoassay is a major detection system of biological materials from patient samples. Our group has been developing a highly sensitive immunoassay system using magnetic nanoparticles made from Fe3O4. Since unbound magnetic markers randomly move in solvent due to Brownian motion, there is no magnetic signal from unbound magnetic markers; therefore, the separation of bound from unbound markers (B/F separation) is not required. This advantage means that the detection time is greatly decreased in comparison with a normal method using fluorescent/enzyme reagent. In this paper, we describe the configuration of the developed system and demonstrate the performance of the detection of magnetic nanoparticles.