A first set of antibodies are bonded to a substrate, and are exposed to and bonded with target antigens. A second set of antibodies are bonded to nanoparticles, and the nanoparticle labeled antibodies are exposed to the targeted antigens. An electromagnetic write-head magnetizes the nanoparticles, and then a read-sensor detects the freshly magnetized nanoparticles. The substrate comprises a flexible film or a Peltier material to allow selective heating and cooling of the antigens and antibodies. Nanoparticles of different magnetic properties may be selectively paired with antibodies associated with different antigens to allow different antigens to be detected upon a single scan by the read-sensor.