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On-Chip Hydrodynamic Chromatography of DNA through Centimeters-Long Glass Nanocapillaries

Abstract

This study demonstrates hydrodynamic chromatography of DNA fragments in a microchip. The microchip contains a highly regular array of nanofluidic channels (nanocapillaries) that are essential for resolving DNA in this chromatography mode. The nanocapillaries are self-enclosed robust structures built inside a doped glass layer on silicon using low-resolution photolithography and standard semiconductor processing techniques. Additionally, the unique nanocapillaries feature a cylindrical interior 600 nm in radius maintained over a length scale 5 cm. The microchip with bare open nanocapillaries is shown to separate a digest of lambda DNA in free solution rapidly (< 5 min under the elution pressure 60 to 120 psi), relying entirely on pressure-driven flows and, doing so, avoiding the field-induced DNA aggregations encountered in gel-free electrophoresis. The nanocapillaries, despite their relatively short length, are observed to fractionate DNA fragments reasonably well with a minimum resolvable size difference below 5 kbp. In the chromatograms obtained, the number of theoretical plates exceeds 105 plates/m for DNA fragments 3.5- and 21-kbp long. The relative mobility of fragments in relation to their size is found in excellent agreement with the simple quadratic model of hydrodynamic chromatography. The model is shown to estimate greater effective hydrodynamic radii than those of respective fragments being unconfined in bulk solution, implying increased drag forces and reduced diffusion coefficients, which is also a noticeable trend among diffusion coefficient estimates derived from the experimentally obtained plate heights. This robust mass-producible microchip can be further developed into a fully integrated bioanalytic microsystem.

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Publication details

The article was received on 22 Mar 2017, accepted on 03 May 2017 and first published on 05 May 2017


Article type: Paper
DOI: 10.1039/C7AN00499K
Citation: Analyst, 2017, Accepted Manuscript
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    On-Chip Hydrodynamic Chromatography of DNA through Centimeters-Long Glass Nanocapillaries

    L. Duan and L. Yobas, Analyst, 2017, Accepted Manuscript , DOI: 10.1039/C7AN00499K

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