Fabrication of a Glass Capillary Electrophoresis Microchip With Integrated Electrodes

In this chapter, a detailed outline delineating the processing steps for microfabricating capillary electrophoresis (CE) with integrated electrochemical detection (ECD) platforms for performing analyte separation and detection is presented to enable persons familiar with microfabrication to enter a cleanroom and fabricate a fully functional Lab-on-a-Chip (LOC) microdevice. The processing steps outlined are appropriate for the production of LOC prototypes using easily obtained glass substrates and common microfabrication techniques. Microfabrication provides a major advantage over existing macro-scale systems by enabling precise control over electrode placement, and integration of all required CE and ECD electrodes directly onto a single substrate with a small footprint. In the processing sequences presented, top and bottom glass substrates are photolithographically patterned and etched using wet chemical processing techniques. The bottom substrate contains seven electrodes required for CE/ECD operation, whereas the top substrate contains the microchannel network. The flush planar electrodes are created using sputter deposition and lift-off processing techniques. Finally, the two glass substrates are thermally bonded to create the final LOC device.