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Separating Beads and Cells in Multi-channel Microfluidic Devices Using Dielectrophoresis and Laminar Flow
Published on: February 5, 2011
Design and analysis of folded channels for chip-based separations
Stewart K Griffiths1, Robert H Nilson
1Sandia National Laboratories, Livermore, California 94551-0969, USA.
Analytical Chemistry
|July 27, 2002
Summary
Band broadening in microchannels is minimized by optimizing turn radius, especially in folded designs. Analytical solutions show specific geometric configurations reduce band dispersion for efficient species transport.
Area of Science:
- Analytical chemistry
- Microfluidics
- Separation science
Background:
- Band broadening in microchannels impacts separation efficiency in electrophoresis and electroosmotic flow.
- Optimizing channel geometry is crucial for minimizing dispersion and enhancing analytical performance.
Purpose of the Study:
- To investigate band broadening in microchannel turns and adjoining segments.
- To determine the minimum turn radius required to minimize turn-induced broadening.
- To evaluate the effect of straight channel segments on broadening in folded configurations.
Main Methods:
- Utilized analytical methods and closed-form solutions.
- Analyzed species transport influenced by electrophoresis and electroosmotic flow.
- Investigated the impact of channel geometry, including turn radius and segment length.
Main Results:
- Turn-induced broadening is negligible when the turn radius exceeds a minimum value (approx. 0.6 * channel width * Peclet number).
- Adjoining straight channel segments in a folded configuration significantly reduce this minimum radius.
- Even short straight segments noticeably decrease the minimum radius required to minimize broadening.
Conclusions:
- Optimized microchannel geometries, particularly folded configurations with specific turn radii and straight segments, can effectively minimize band broadening.
- These findings are applicable to the design of folded and spiral microchannels for improved separation efficiency.
- Novel pleated and coiled geometries are proposed for compact microchannel layouts.
