Abstract

3D Sensing and Integration for Lab on a Chip Devices

Carlotta Guiducci, Professor, EPFL

Electric fields can be effectively used to sense, manipulate and move cells in lab-on-a-chip devices. Nevertheless, the existing implementations don’t meet the high-throughput requirements of single-cell analysis, mostly due to the design limitations entailed by planar electrodes in microfluidic configurations. These could be overcome by vertical electrodes, either integrated in microchannel sidewalls or as free-standing structures. We proposed a new approach to achieve arrays of singularly-addressable vertical elements generating highly-confined electric fields for sensing or manipulating individual cells. Our approach is based on the conformal coating of passive cores with metal layers, defining electrodes in microfluidic channels with high aspect-ratio and vertical uniformity. This method achieves high electrodes density, granting high conductivity of both connections and metal sidewalls with no need for electroplating. The resulting vertical electrodes span the full height of the microfluidics, generating homogeneous fields along the z-axis of the channel. This technology has been employed for high-performance impedance cytometry and to constitute arrays of microtraps for on-chip single-cell analysis.