A biosensor based on magnetoresistance technology.

We are developing a biosensor that will measure, at the level of single molecules, the forces that bind DNA-DNA, antibody-antigen, or ligand-receptor pairs together. The Bead Array Counter (BARC) will use these interaction forces to hold magnetic microbeads to a solid substrate. Microfabricated magnetoresistive transducers on the substrate will indicate whether or not the beads are removed when pulled by magnetic forces. By adapting magnetoresistive computer memory technology, it may be possible to fabricate millions of transducers on a chip and detect or screen thousands of analytes. The multi-analyte capability of this portable sensor would be ideal for on-site testing, while the potential to directly gauge intermolecular interaction strengths suggests drug discovery applications.