An Immunoassay Platform Based on CMOS Hall Sensors

We describe an immunoassay utilizing standard CMOS technology. An array of Hall sensors is used to detect the magnetic beads that serve as the assay signal. Electrical and magnetic modulation is employed to improve the sensitivity of the sensors. The devices receive two post-processing steps to improve sensitivity and biocompatibility. We have fabricated prototype devices using a 0.25-μm BiCMOS process, and have successfully detected anti-Hu IgG antibody at a concentration of 200pM.