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Issue 10, 2008
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Electrokinetically driven fluidic transport in integrated three-dimensional microfluidic devices incorporating gold-coated nanocapillary array membranes

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Abstract

Electrokinetically driven fluid transport was evaluated within three-dimensional hybrid nanofluidic–microfluidic devices incorporating Au-coated nanocapillary array membranes (NCAMs). Gold NCAMs, prepared by electroless gold deposition on polymeric track-etched membranes, were susceptible to gas bubble formation if the interfacial potential difference exceeded ∼2 V along the length of the gold region. Gold membranes were etched to yield 250 μm wide coated regions that overlap the intersection of two orthogonal microfluidic channels in order to minimize gas evolution. The kinetics of electrolysis of water at the opposing ends of the gold region was modeled and found to be in satisfactory agreement with experimental measurements of the onset of gas bubble formation. Conditions to achieve electrokinetic injection across Au-coated NCAMs were identified, with significant reproducible injections being possible for NCAMs modified with this relatively thin gold stripe. Continuous gold films led to suppressed injections and to a variety of ion enrichment/depletion effects in the microfluidic source channel. The suppression of injections was understood through finite element modeling which revealed the presence of a significant electrophoretic velocity component in opposition to electroosmotic flow at the edge of the Au-dielectric regions.

Graphical abstract: Electrokinetically driven fluidic transport in integrated three-dimensional microfluidic devices incorporating gold-coated nanocapillary array membranes

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Publication details

The article was received on 08 Apr 2008, accepted on 16 Jun 2008 and first published on 08 Aug 2008


Article type: Paper
DOI: 10.1039/B805768K
Citation: Lab Chip, 2008,8, 1625-1631
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    Electrokinetically driven fluidic transport in integrated three-dimensional microfluidic devices incorporating gold-coated nanocapillary array membranes

    A. Piruska, S. Branagan, D. M. Cropek, J. V. Sweedler and P. W. Bohn, Lab Chip, 2008, 8, 1625
    DOI: 10.1039/B805768K

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