Method and fluidic microsystem for the dielectrophoretic manipulation of suspended particles

A method for operating a fluidic microsystem for dielectrophoretic manipulation of suspended particles having a predetermined particle diameter in a suspension liquid, wherein the fluidic microsystem comprises:

• a channel having a longitudinal direction,
• an electrode device having an elongate electrode, a longitudinal extension of which deviating from a longitudinal direction of the channel and which has a plurality of individually activatable electrode segments for generating dielectrophoretic forces acting on the suspended particles, wherein each electrode segment has a deflection angle relative to the longitudinal direction of the channel and a segment length, which determine a segment offset transverse to the longitudinal direction of the channel, and
• a control device by way of which the electrode segments can be activated,
• wherein the method comprises the steps:
• generating a flow of the suspension liquid with a flow velocity in the channel, so that the suspended particles in succession pass an interaction region of the elongate electrode which is spanned by the electrode segments,
• activating the electrode segments in order to deflect the suspended particles in the channel onto predetermined movement paths which are determined by a superposition of flow forces in the flow of the suspension liquid and the dielectrophoretic forces generated at the electrode segments, wherein
• as each particle passes, each of the electrode segments which the particle passes in succession is activated in a clocked manner by the control device in dependence on a desired movement path in each case for a predetermined activation time, wherein the activation time of each electrode segment is determined by a quotient of the segment length of the electrode segment and the flow velocity, and
• the electrode segments are so dimensioned that the segment offset of each electrode segment is smaller than the particle diameter, and in each case at least two successive electrode segments cooperate for a deflection of each particle.

A fluidic microsystem configured for the dielectrophoretic manipulation of particles having a predetermined particle diameter in a suspension liquid, comprising:

• a channel having a longitudinal direction,
• an electrode device having an elongate electrode, the longitudinal extension of which deviating from the longitudinal direction of the channel and which has a plurality of individually activatable electrode segments for generating dielectrophoretic forces acting on the particles, wherein each electrode segment has a deflection angle relative to the longitudinal direction of the channel and a segment length, which determine a segment offset transverse to the longitudinal direction of the channel, and
• a control device by way of which the electrode segments can be activated, wherein
• the channel is configured to receive a flow of the suspension liquid with a flow velocity such that the suspended particles pass in succession through an interaction region of the electrode which is spanned by the electrode segments, wherein
• the control device is configured to activate the electrode segments in order to deflect the particles in the channel onto predetermined movement paths which are determined by a superposition of flow forces in the flow of the suspension liquid and the dielectrophoretic forces generated at the electrode segments,
• the control device is configured, as the particles pass, to activate in a clocked manner each of the electrode segments which one of the particles passes in succession in dependence on a desired movement path in each case for a predetermined activation time, wherein the activation time of each electrode segment is determined by a quotient of the segment length of the electrode segment and the flow velocity,
• the electrode segments are so dimensioned that the segment offset of each electrode segment is smaller than the particle diameter, and
• the control device is configured to activate the electrode segments so that in each case at least two successive electrode segments cooperate for the deflection of each particle.