Method and fluidic microsystem for the dielectrophoretic manipulation of suspended particles

Abstract

The invention relates to a method for operating a fluidic microsystem () for the dielectrophoretic manipulation of suspended particles () having a particle diameter in a suspension liquid (), wherein the microsystem () comprises: —a channel () having a longitudinal direction; —an electrode device () having an electrode (), the longitudinal extent of which deviates from the longitudinal direction of the channel () and which has individually controllable electrode segments () for producing dielectrophoretic forces which act on the particles (), each electrode segment () having a deflection angle α, relative to the longitudinal direction of the channel (), and a segment length (s), which determine a segment offset (D) perpendicular to the longitudinal direction of the channel (); and —a control device (). The method comprises: —producing a flow of the suspension liquid () with a flow velocity so that the particles () successively pass through an interaction region of the electrode (), which interaction region is spanned by the electrode segments (); and —activating the electrode segments () in order to deflect the particles () onto predetermined motion paths (), which are determined by a superposition of flow forces in the flow of the suspension liquid () and of the dielectrophoretic forces at the electrode segments (). During the passage of each particle, each of the electrode segments () which are passed by the particle () is activated in a clocked manner for a predetermined activation duration, according to the desired motion path (), the activation duration of each electrode segment () being determined by the quotient of the segment length (s) of the electrode segment () and the flow velocity. The electrode segments () are dimensioned such that the segment offset (D) of each electrode segment () is less than the particle diameter. For the deflection of each particle (), at least two successive electrode segments () cooperate.