Microcoils are integrated with -well Hall sensors in a complementary metal-oxide-semiconductor (CMOS) integrated circuit for the detection of individual superparamagnetic beads. The -wide microcoils, generating magnetic fields of with of current, are used to polarize beads of in diameter. The resulting magnetization field induced in the bead is measured by a Hall sensor, stacked below the microcoil. The detection system has a sensitivity and resolution of and , respectively. Integration of the magnetic bead detection onto a CMOS platform drastically reduces system cost, complexity, and power consumption, and marks an important milestone on the road to implementing low-cost, easy-to-use, point-of-care diagnostic assay.
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