The Limit of Detection of Giant Magnetoresistive (GMR) Sensors for Bio-applications

Abstract

For the detection of specific bio-molecules, such as cells, proteins and DNA, it is necessary to verify the limit of detection (LOD) of an investigated giant magnetoresistive (GMR) sensor. We measured voltage drops across a GMR sensor before and after spreading magnetic particles oil the surface of the GMR sensor and compared them to find the LOD of the GMR, sensor. Magnetic particles (Dynabeads (R)) of 2.8 mu m in diameter were used. The threshold for the detection was approximately 6 beads. This result indicates that the GMR, sensor studied in this study can be used to detect bio-molecules, such as micron-sized cells.