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Microfluidic Chips Controlled with Elastomeric Microvalve Arrays
Published on: October 1, 2007
Automated electric valve for electrokinetic separation in a networked microfluidic chip
Huanchun Cui1, Zheng Huang, Prashanta Dutta
1School of Chemical Engineering and Bioengineering and School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164, USA.
Analytical Chemistry
|February 15, 2007
Summary
This study introduces an automated electric valve system for microfluidic chips. The system effectively reduces dispersion and sample loss during electrokinetic separations, improving reproducibility for charged species.
Area of Science:
- Microfluidics
- Analytical Chemistry
- Electrokinetics
Background:
- Dispersion and sample loss occur at T-junctions in microfluidic chips during electrokinetic separations.
- Controlling current streamlines is crucial for minimizing dispersion, especially in the absence of electroosmotic flow.
Purpose of the Study:
- To develop and evaluate an automated electric valve system to reduce dispersion and sample loss at microfluidic T-junctions.
- To improve the performance of electric valves during nonlinear electrophoresis (isotachophoresis).
Main Methods:
- Computer simulations were used to model the effect of electric fields on current streamlines.
- An automated electric valve system with integrated platinum microelectrodes was designed and implemented.
- Experiments were conducted to evaluate valve performance using protein zones during isotachophoresis.
Main Results:
- Simulations showed that an additional electric field can straighten current streamlines, reducing dispersion.
- Initial electric valve designs showed unsatisfactory performance during isotachophoresis.
- The automated electric valve system demonstrated decreased dispersion and increased reproducibility in experiments.
- Simulations confirmed that the automated system maintained desired current streamline shapes during isotachophoresis.
Conclusions:
- Automated electric valves integrated into microfluidic chips are effective for manipulating current streamlines.
- This technology significantly reduces dispersion and sample loss for charged species in electrokinetic separations.
- The developed system offers improved performance and reproducibility, particularly for complex separation techniques like isotachophoresis.
