Design and realization of a microfluidic system for dielectrophoretic colloidal handling

Abstract

Precise spatial localization of colloids is required to fully exploit the potential of colloidal handling in a microfluidic channel. In this work, we present the fabrication and integration of a new type of microfluidic chip that can provide such tools. With the use of photopatternable silicones, two levels of metal deposited electrodes are sandwiching a microchannel layer, whom height is precisely control. The microfabrication process does not require extra etching step for eventual residual layer, thus making electrical contact between the fluid in the channel and electrodes on the upper and lower slices. The chip is integrated in an experimental bench that addresses up to 120 electrodes immerged and aligned into the channel itself. This high level of integration makes colloidal handling with dielectrophoresis possible thanks to the introduction of several key functions such as focus, defocus, stop or vectorial path. Finally, first results are presented with the quantification of the influences of the applied potential frequency and peak-to-peak voltage for the stop function with 1 μm polystyrene colloids under a 600 μl/min flow, highlighting optimal frequency for this function.