Monolithic fabrication of nanofluidic artificial gel media for DNA electrophoresis

A new technique for fabricating two-dimensional artificial gels for DNA electrophoresis is presented. The technique differs from previous approaches in that the entire device is fabricated as a monolithic unit using exclusively planar processing techniques borrowed from semiconductor electronics fabrication. The height of the fluid gap between the dielectric floor and ceiling is determined by the thickness of a sacrificial layer which is removed by a wet chemical etch. This allows precise control and excellent uniformity of the gap over an entire silicon wafer. Gap control better than 5 nm has been demonstrated for floor-to-ceiling height for the fluid gap. The lateral resolution which can be attained is limited only by available lithographic techniques. In this work, 1 μm diameter pillars are defined with i-line photolithography. Fluid interconnects are established with a liquid meniscus to the edge of the device.