A 0.3ppm dual-resonance transformer-based drift-cancelling reference-free magnetic sensor for biosensing applications

Abstract

Cost-efficient, point-of-use diagnostics are critical for early disease detection. Traditionally, the majority of lab-based analysis equipment utilizes fluorescent markers for biodetection assays. However, magnetic-based labels have recently been shown to be promising alternatives to fluorescent tags for DNA, protein, and cell assays. Magnetic assays offer several key advantages over their fluorescent counterparts, namely that magnetic beads do not suffer from signal decay due to bleaching and that they can be detected with cheap CMOS-based sensors, eliminating the need for expensive lasers, photo-diodes, filters, and complicated post-processing steps. Significant progress has recently been made in the design of magnetic imager ICs, such as [1] which utilizes a gMr approach for detection and [2-4] which measure the resonance shift in an LC tank.