High-Throughput, Continuous-Flow Separation of Biomolecules in a High-Aspect-Ratio Nanofilter Array

We have developed a novel fabrication approach to generate massively-parallel, high-aspect-ratio vertical nanofluidic channels with smooth, vertical sidewalls and precise control of uniform gap sizes (lateral trench width) down to 50 nm. The aspect ratio can be as high as 400 and the channel depths are more than 20µm. This technique enables us to fabricate a large area of solid membrane structures with well-de¬fined pore size and geometries, which can be very useful for membrane-based application such as filtration, separation and fuel cells. Also, using such systems as molecular sieving filters, we demonstrated efficient continuous-flow size-fractionation of large DNA molecules in a two-dimensional (2D) vertical nanofilter array device fabricated by this method. The device allows much higher sample volume processing rate (1µL/hour), compared with the planar nanofilter array chip previously reported. We believe that these devices could be a key to the efficient proteomic sample preparation microsystems as well as useful in purifying and separating various bioparticles and nanoparticles.