High-resolution separation of DNA/proteins through nanorod sieving matrix

In this paper, we report on an integrated nanorod array as a novel sieving matrix for high-resolution separation of biomolecules. A wide size range of DNA (100 bp-166 kbp) and proteins (11.4 kDa-205 kDa) are resolved into sharp peaks within several minutes using devices with various pore apertures, either in a reptation mode or Ogston mechanism. The device delivers notable performance with the minimum resolvable size difference 10 bp for 100 bp and 150 bp DNA fragments, 15.9 kbp for 48 kbp and 166 kbp DNA chains, and 7.9 kDa for 11.4 and 68 kDa proteins, where the separation efficiency is higher than or comparable to other micro/nanofabricated artificial sieving structures. The process utilizes localized oblique angle deposition (LOAD) to simply integrate densely packed nanorods onto steep sidewalls of microfluidic channels, which eliminates the requirement of advanced lithography tools routinely used in conventional artificial sieving structures. We further demonstrate the modulation of pore aperture that employs the sculptured sidewalls by a custom deep reactive-ion etching (DRIE) recipe. Given the easy fabrication, excellent engineering control and outstanding sieving capability, this nanorod sieve device has great potentials to provide a simple and effective separation technique for biomolecule analysis.