Magnetic particle biosensors

Abstract

With the discovery of the GMR effect in the mid 1980s, magnetic sensing has emerged as having great potential of being a highly sensitive biosensor. We hence used this method to undertake systematic studies on the response of a MR sensor to a single ferromagnetic or paramagnetic particle. Spin valve sensors were designed and fabricated, and we used the method of atomic force microscope and optical tweezers for the manipulation and subsequent detection of single particles. Our results is explained by a simple model where the particle is treated as a pure magnetic dipole.We also propose a version of magnetic twisting cytometry for the study of single cell mechanics, where a SV sensor is used to measure the angle of rotation in a single ferromagnetic particle attached to the surface of a single human Mesenchymal Stem Cell which we believe can create a platform for single cell characterization.