Scanned micro-Hall microscope for detection of biofunctionalized magnetic beads

Here the authors report a scanned micro-Hall system capable of detecting single micron-sized paramagnetic beads at high scan rates over a wide scan area. Very small changes in local fields (< 1 mu T/root Hz) are detected in the presence of a large dc polarizing field. The sensor is noninvasive, operates at room temperature, and could be operated in liquids. These attributes make the system particularly suitable for biological applications. For example, it provides the potential for integration of biofunctionalized beads with specific biomarkers for highly sensitive detection.