| Technology for detecting biomolecules is an integral part of early cancer diagnosis research. Various sensors based on fluorescence, mass, electrical interactions, etc., have been developed to detect cancer biomarkers. In this dissertation, a giant magnetoresistive (GMR) sensor is presented for biomolecule detection. The GMR sensor can detect small changes in local magnetic field. If a target biomolecule is labeled with a magnetic nanoparticle and a specific probe is coated on the sensor surface, the target molecule will be captured on the sensor surface. When an external magnetic field is applied to magnetize this magnetic nanoparticle, the stray field from the particle can be detected by the GMR sensor. In this dissertation, various components of the GMR sensor technology are described and several examples of the application of the GMR sensor are presented. Compared with other technologies for biomolecule detection such as fluorescent based biosensors, GMR sensor is more sensitive, can be easily integrated with electronics and microfluidics, and can be made portable. In addition, GMR sensor and measurement system is much less expensive than mort of other detection methods. Therefore, GMR sensor is a good candidate for detecting biomolecules including cancer biomarkers. In addition, it is shown in preliminary experiments that GMR sensor can be used to study the kinetics of biomolecule interactions, and therefore can serve as a complementary technology to Surface Plasmon Resonance (SPR), which is the dominant technology currently used for kinetics measurement. |
