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Micro magnetic stir-bar mixer integrated with parylene microfluidic channels
Kee Suk Ryu1, Kashan Shaikh, Edgar Goluch
1Micro Actuators, Sensors and Systems Group, Micro and Nanotechnology Laboratory, Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Lab on a Chip
|December 1, 2004
Summary
This study presents a new microfluidic device with an integrated magnetic stir-bar in parylene channels, improving mixing and eliminating PDMS channel issues like cross-contamination. The device also demonstrates liquid pumping capabilities.
Area of Science:
- Microfluidics
- Materials Science
- Mechanical Engineering
Background:
- Previous work utilized polydimethyl-siloxane (PDMS) microchannels with external magnetic stir-bars.
- PDMS channels exhibit limitations including porosity, leading to evaporation, absorption, and cross-contamination.
- Manual alignment of PDMS to glass substrates presented assembly challenges.
Purpose of the Study:
- To fabricate and test a micro magnetic stir-bar monolithically integrated within parylene surface-micromachined channels.
- To improve microfluidic mixing performance and address limitations of PDMS-based systems.
- To demonstrate the dual functionality of the integrated magnetic stir-bar for mixing and pumping.
Main Methods:
- Fabrication of parylene surface-micromachined microchannels.
- Monolithic integration of a micro magnetic stir-bar with a small tolerance (10 microm) to the channel wall.
- Testing of mixing efficiency using the integrated magnetic stir-bar driven by an external rotating magnetic field.
- Evaluation of liquid pumping capabilities of the magnetic stir-bar.
Main Results:
- Achieved improved mixing performance in parylene microchannels compared to previous PDMS systems.
- Eliminated issues associated with PDMS porosity, such as chemical absorption, evaporation, and cross-contamination.
- Demonstrated successful monolithic integration of the magnetic stir-bar with precise stir-bar-to-wall tolerance.
- Successfully utilized the magnetic stir-bar for liquid pumping in microchannels.
Conclusions:
- Parylene-based microchannels with integrated magnetic stir-bars offer superior performance and reliability over PDMS systems.
- The monolithic integration and improved design overcome key limitations of prior microfluidic mixers.
- The demonstrated dual function of mixing and pumping expands the utility of this microfluidic platform.