Abstract: A method for controlling the movement of magnetic or magnetizable objects (10) in a biosensor cartridge. The method comprises the step of providing a biosensor cartridge with a laterally extending sensor surface (A) and at least a magnetic field generating means (20, 30, 30?) for generating a magnetic field with a field gradient substantially perpendicular to the sensor surface (A). The magnetic field generating means (20, 30, 30?) are alternatingly actuated such that the generated magnetic field directs alternatingly the magnetic or magnetizable objects (10) substantially perpendicular to the sensor surface (A) away and toward the sensor surface, wherein pulse lengths of the alternating actuation are adjusted such that a lateral movement of magnetizable objects along the laterally extending sensor surface is substantially avoided.

Abstract: The invention relates to a method and a device (100) for determining the amount of a target component (2) in a sample, wherein magnetic particles (2) can bind to a contact surface (4) with kinetics that depend on the sample-amount of the target component. The method comprises at least two washing steps during which magnetic particles (2) are magnetically moved away from the contact surface (4) and corresponding measurements of the remaining amount of magnetic particles (2) at the contact surface (4). The amount of target component in the sample is estimated from at least one of such measurement results. The measurement allows to determine also high concentrations of target component for which the sensor surface (4) is saturated in a steady-state.

Abstract: The invention relates to a system and a method for the detection of target components (102) in a sample with the help of indicator particles (101) distributed in said sample. The distance (d) between indicator particles (101) and a contact surface (112) is determined after the target components could bind to the contact surface and/or the indicator particles. Thus it is possible to detect how many target components (102) are bound without a need for a binding between indicator particles (101) and contact surface (112). Optionally the indicator particles (101) can be affected by a modulated force, e.g. via an electromagnet (141). The determination of the distance (d) between indicator particles (101) and contact surface (112) may for example be achieved by frustrated total internal reflection, measurement of magnetic fields, or FRET.