Comparison of Various Channel Fabrication Methods for Microchip Electrophoresis

Five different methods are compared for microchip channel fabrication, namely: deep reactive ion etching, wet chemical etching, sawing, sandblasting and laser ablation. The first four methods were developed for manufacturing glass materials and laser ablation for plastic materials. Sand blasting and sawing techniques are based on mechanical erosion, therefore, the instrumentation these processes require is simpler and more cost effective than that of processes based on photolithography and chemical erosion. The other advantage of mechanical erosion based methods is reduced processing time. Sawing by means of a resinoid blade gave comparable channel quality with channels created by etching processes and a simple channel structure was created within one hour. However, to create identical channels on multiple chips it is advisable to use chemical erosion techniques where quite a few chips can be structured under the same microfabrication process, while by sawing or sandblasting only one chip is usually processed. For rapid prototyping and testing, sawing proved to be very beneficial as it did not require clean-room environment, and therefore was readily available for most regular laboratories with the inteant to enter the field of microfluidics based analytical techniques.