Patent ID: 6468809
Filing Date: 2002-10-22
Classification: G01N,G11C

Abstract:
A sensing device for immobilizing and detecting the presence of a magnetic particle in a binding assay, the sensing device comprising:(i) a magnetic sensing element comprising at least one planar layer of electrically conductive ferromagnetic material having an initial state in which the material has a circular magnetic moment within the plane of the layer, the magnetic sensing element having molecules of a first specific binding member attached thereto, the molecules of the first binding member being selected and located so that they are capable of directly or indirectly immobilizing a magnetic particle in a binding assay in a position with respect to the planar layer such that the fringing field of the magnetic particle is able to cause the magnetic moment of at least one layer of electrically conductive ferromagnetic material to shift from circular to radial, thereby causing a detectable change in the electrical resistance of the magnetic sensing element, and (ii) means to detect the change in the electrical resistance of the magnetic sensing element.