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Sample transport and electrokinetic injection in a microchip device for chemical cytometry.

ABSTRACT: Sample transport and electrokinetic injection bias are well characterized in capillary electrophoresis and simple microchips, but a thorough understanding of sample transport on devices combining electroosmosis, electrophoresis, and pressure-driven flow is lacking. In this work, we evaluate the effects of electric fields from 0 to 300? V/cm, electrophoretic mobilities from 10(-4) to 10(-6) ?cm(2)/Vs, and pressure-driven fluid velocities from 50 to 250? ?m/s on sample injection in a microfluidic chemical cytometry device. By studying a continuous sample stream, we find that increasing electric field strength and electrophoretic mobility result in improved injection and that COMSOL simulations accurately predict sample transport. The effects of pressure-driven fluid velocity on injection are complex, and relative concentration values lie on a surface defined by pressure-driven flow rates. For high-mobility analytes, this surface is flat, and sample injection is robust despite fluctuations in flow rate. For lower mobility analytes, the surface becomes steeper, and injection depends strongly on pressure-driven flow. These results indicate generally that device design must account for analyte characteristics and specifically that this device is suited to high-mobility analytes. We demonstrate that for a suitable pair of peptides fluctuations in injection volume are correlated; electrokinetic injection bias is minimized; and electrophoretic separation is achieved.

SUBMITTER: Kovarik ML

PROVIDER: S-EPMC3516882 | biostudies-literature | 2011 Nov

REPOSITORIES: biostudies-literature

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Sample transport and electrokinetic injection in a microchip device for chemical cytometry.

Kovarik Michelle L ML Lai Hsuan-Hong HH Xiong Jessie C JC Allbritton Nancy L NL

Electrophoresis 20111020 22

Sample transport and electrokinetic injection bias are well characterized in capillary electrophoresis and simple microchips, but a thorough understanding of sample transport on devices combining electroosmosis, electrophoresis, and pressure-driven flow is lacking. In this work, we evaluate the effects of electric fields from 0 to 300 V/cm, electrophoretic mobilities from 10(-4) to 10(-6) cm(2)/Vs, and pressure-driven fluid velocities from 50 to 250 μm/s on sample injection in a microfluidic ...[more]

PMID: 22012764

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Sample transport and electrokinetic injection in a microchip device for chemical cytometry.

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Sample transport and electrokinetic injection in a microchip device for chemical cytometry.

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