Abstract

With the recent technological advances in the synthesis and characterization of nano- and microparticles, there has been a growing interest in applying this technology to different areas, such as diagnosis of diseases and detection of pollutants. The use of magnetic particles as biosensors is favored due to the mobility of magnetic particles under magnetic fields and the low magnetic background observed in most biological samples. This chapter briefly discusses the basic ways to modify the surface of magnetic particles to enhance interaction with biological targets, and thoroughly reviews the different applications of magnetic particles as biosensors. The use of magnetic particles is divided into three categories by the functionality of the magnetic particles in these biosensors, namely magnetic particles as carriers for signal intensification, magnetic particles as labels to detect magnetic contents, and bio-sensing based on the dynamics of magnetic particles. The strategy and theory of different magnetic particle biosensors are elucidated in details and illustrated through examples.