Dissertation
Nonlinear electrophoresis in networked microfluidic chips
Washington State University
Doctor of Philosophy (PhD), Washington State University
12/2007
DOI:
https://doi.org/10.7273/000005702
Abstract
This dissertation reports the implementation of two major nonlinear electrophoretic techniques (isoelectric focusing and isotachophoresis) onto networked microfluidic chips. A number of improvements have been made to address the issues that occurred during the miniaturization of those two techniques. Ampholyte-based isoelectric focusing was first demonstrated in a single-channel poly(dimethylsiloxane) chip in which experimental conditions had been optimized to mitigate the adverse effects on the separation resolution due to the problems such as electroosmotic flow, peak drift and pH gradient compression. The resolving power of isoelectric focusing was then further improved in networked microfluidic chips by a staging method. This method couples several stages of IEF in series by first focusing proteins in a straight channel using broad-range ampholytes and then refocusing segments of the first channel into secondary channels that branch from the first one at Tjunctions.; Isotachophoresis experiments demonstrated that a mixture of three fluorescent proteins can be concentrated and stacked into adjacent zones of pure protein in a microchannel. Two-dimensional model was developed to illustrate the stacking and separation features of isotachophoresis and to explore its self-sharpening behavior of sample zones dispersed a T-junction. Sample dispersion at the T-junction was reduced by implementation of an electric valve. With an automated control system, the electric valve utilizing a pair of integrated microelectrodes provided an effective way to maintain current streamlines, thus preventing charged species from dispersion into the T-junction.
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Details
- Title
- Nonlinear electrophoresis in networked microfluidic chips
- Creators
- Huanchun Cui
- Contributors
- Cornelius F. Ivory (Chair)
- Awarding Institution
- Washington State University
- Academic Unit
- School of Chemical Engineering and Bioengineering
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 140
- Identifiers
- 99901054941101842
- Language
- English
- Resource Type
- Dissertation