Scanning Magnetic Tunnel Junction Sensor for the Detection of Magnetically Labeled DNA Microarray

In this paper, we introduce a magnetic scanning probe microscope based on a single magnetic tunnel junction (MTJ) sensor with a sensitivity of 4V/mT to detect magnetic particles on DNA microarray. We demonstrate the direct measurement of the magnetic dipole fields associated with both micron size ferromagnetic nickel thin film patterns and monodispersed paramagnetic particles tagged to surface immobilized DNA by large area 2D scanning of sensor over the sample with scan speed of ~500 μm/s.