High-throughput design and fabrication of an integrated microsystem with high aspect-ratio sub-micron pillar arrays for free-solution micro capillary electrophoresis

A new technology approach for the design, fabrication and application of an integrated free-solution capillary electrophoresis microsystem is presented. Combining the advantages of projection, contact photolithography and deep-reactive-ion-etching, this approach allows fast and flexible formation of micron-sized channels integrated with extremely high aspect-ratio (>50: 1) sub-micron pillar arrays on a silicon substrate. Utilizing fluorescence video microscopy, free-solution DNA separation has been demonstrated. Furthermore, the detailed DNA molecular interaction with the pillars inside the microsystem can be analysed. In comparison with the previously reported fabrication technologies, such as electron beam lithography, the newly presented technology approach offers a significant improvement in fabrication time and design flexibility; both are highly desirable not only for potential commercialization of the free-solution electrophoresis microsystem in applications such as lab-on-a-chip but also for systematic studies of micro-scale DNA kinetics.