ABSTRACT

Magnetic biosensors, particularly giant magnetoresistive (GMR) biosensors based on spin-valve sensors, used to detect surface binding reactions of biological molecules labeled with magnetic particles possess the potential to compete with fluorescent-based biosensors, which currently dominate the application space in both research and clinical settings. Magnetic biosensing offers several key advantages over conventional optical techniques and other competing sensing modalities. First, the samples (blood, urine, serum, etc.) naturally lack any detectable magnetic content, providing a sensing platform with a very low background. Additionally, magnetic tags do not suffer from problems that have plagued fluorescent labels such as label-bleaching and autofluorescence. Second, the sensors can be arrayed and multiplexed to perform complex protein or nucleic acid analysis in a single assay without resorting to optical scanning. Finally, the sensors are compatible with standard silicon integrated circuit (IC) technology, allowing them to be manufactured cheaply with integrated electronic readout in mass quantities and to be deployed in a single-use, disposable format. The technology is scalable and capable of being integrated, making it appealing for point-of-care (POC) testing applications.