On Detection of Magnetic Nanoparticles Using a Commercial GMR Sensor

This paper describes the research for implementing a commercial giant magnetoresistive (GMR) sensor for detection of magnetic nanoparticles with potential applications in lab on a chip (LOC) device or for analysis of waste water. Micromagnetic simulations are performed to illustrate the behaviour of the detection system. The experimental setup focuses on the detection of polyethylene glycol (PEG6000) functionalized magnetic nanoparticles, commonly used in biosensors and LOC devices. Practical solutions for improving the GMR sensor measurement setup are detailed and discussed. From the experimental measurements we are able to detect a mass approximately 1.20 μg of pure maghemite cores which corresponds to a magnetic moment of approximately 9.098∙10-5 emu for a signal variation of 0.035 V. (in this case, a detection sensitivity of about 75.81 emu/g). Emphasis is placed on advantages in terms of setup sensitivity, flexibility and integration.