Enhanced Separation Performance in Microfabricated Electrophoresis Devices by Electric Field Induced Collection and Metering of DNA

摘要

Microfluidic technology is a key component in the development of microfobricated lab-on-a-chip systems for use in bioanalytical and biosensing applications. These devices continue to be developed to perform a variety of DNA analysis assays, however many of these applications deal with such minute amounts of DNA that it must first be pre-concentrated to a detectable level. On the macroscale, this pre-concentration is typically performed using centrifugation processes which are difficult to miniaturize and interface with other microfluidic components. In order to address this issue, we have developed microfluidic devices incorporating arrays of on-chip electrodes to locally increase the concentration of DNA in solution. By applying a low voltage (～1-2V) between neighboring microfabricated electrodes positioned inside a microfluidic channel, the intrinsically negatively charged DNA fragments are induced to migrate towards and collect at the anode, thereby allowing the quantity of accumulated DNA to be precisely metered. We demonstrate the application of this technique in electrophoresis microchips to inject a well defined narrow and concentrated DNA plug into an electrophoresis gel, resulting in enhanced resolution of the separating bands.