A biochip based on magnetoresistive sensors

The signal response of Bangs Laboratories magnetic markers with a mean diameter of 0.86 [micro]m on a spiral-shaped giant magnetoresistance sensor with a diameter of 70 [micro]m is investigated. The data show a linear dependence of the sensor signal on the surface coverage of the magnetic markers. The detection limit is reached at a coverage of about 5%, which corresponds to about 200 markers distributed across the surface of the sensor. The corresponding molecular binding of the analyte DNA and the magnetic markers show good selectivity and sensitivity. Index Terms--Biomagnetics, biomedical measurements, magnetoresistive devices, sensors.