Construction and validation of simple magnetic nanoparticle detector based on giant magnetoresistive effect

Abstract

The finding of giant magnetoresistive(GMR) effect develops a new field for the sensing application with magnetic nanoparticles(MNPs) labeling. A convenient GMR sensor was built with a permanent magnet to excite the MNPs in this work. The sensing element contained a Wheatstone bridge with the GMR material as one of its branches. The magnetic field from MNPs unbalanced the Wheatstone bridge. After being amplified, the output signals were recorded. The construction and optimization of the magnetoresistive sensing platform were discussed in detail. The detection of three kinds of MNPs validated the performance of the proposed GMR sensor. The sensor showed a fast response to the addition or removal of MNPs. Because of its simplicity, this kind of GMR sensor can be developed in a routine laboratory. The finding of this new GMR sensor will promote the development of the method of probing biomolecules and the study on the biomolecular interaction after being labeled magnetically.