High-throughput, Continuous-flow Separation of Biomolecules in a High- aspect-ratio Nanofilter Array

We have developed a novel fabrication ap proach to generate massively-parallel, highaspect-ratio vertical nanofluidic channels with smooth, vertical sidewalls and precise control of uniform gap sizes (lateral trench width) down to 50 nm (Figure 1) [1]. The aspect ratio can be as high as 400 and the channel depths are more than 20 μm. This technique enables us to fabricate a large area of solid membrane structures with well-defined 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 (Figure 2). Our device allows much higher sample volume processing rate (1μL/hour), compared with the planar nanofilter array chip previously reported [2]. 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. Figure 1: (A) Schematic diagram of fabricating massively-parallel vertical nanofluidic membranes. (B) Cross-sectional SEM micrograph of vertical nanochannels with lateral gap sizes (widths) of 250 nm, 200 nm, and 30 nm. p