Abstract: The invention relates to a magnetic system for biosensors and in particular to a magnetic system which can switch between attraction force and repulsion force near the sensor surface with more easy but also more effective means. This is realised with at least one coil (2) and at least two ferromagnetic cores (3) which are arranged in a concentric multilayered package, and a sensor or a sensor surface exposed to or covered with the biomaterial, which is arranged near to the magnetic system.

Abstract: The invention relates to a magnetic system for biosensors. It aims at developing a magnetic system for biosensors, which can switch between attraction force and repulsion force near the sensor surface. The arrangement has at least a coil and a ferromagnetic core generating a magnetic field, and a sensor or sensor surface which corresponds with the magnetic field in a way, that the ferromagnetic core is equipped with an opening on the side where the sensor is located in order to produce a local high density of inhomogeneous magnetic field lines, along which the sensor is movable between at least two definable positions.