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A robust, portable and backflow-free micromixing device based on both capillary- and vacuum-driven flows.
Yaguang Zhai1, Anyang Wang, Domin Koh
1SMALL (Sensors and MicroActuators Learning Lab), Department of Electrical Engineering, University at Buffalo, The State University of New York (SUNY at Buffalo), Buffalo, New York 14260, USA. kwangoh@buffalo.edu.
Lab on a Chip
|December 5, 2017
Summary
This study presents a novel micromixing device that prevents liquid backflow using a pressure-balancing bypass. The device successfully demonstrated blood typing and has potential for point-of-care diagnostics.
Area of Science:
- Microfluidics
- Biomedical Engineering
- Analytical Chemistry
Background:
- Surge backflow is a common issue in capillary- or vacuum-driven microfluidics when merging liquids.
- Existing microfluidic devices often struggle with pressure differences caused by capillarity and gravity, leading to backflow events.
Purpose of the Study:
- To design, fabricate, and characterize a robust, portable micromixing device insensitive to backflow.
- To develop a microfluidic system that enables synchronous liquid stream entry into a dead-end channel without backflow.
- To demonstrate the device's utility in blood group determination and agglutination-based assays.
Main Methods:
- A capillary-driven pressure balancing bypass was integrated to diminish initial pressure differences.
- Syringe-assisted vacuum-driven pumping utilizing polydimethylsiloxane's gas permeability was employed.
- The device was tested by mixing colored dyes and performing ABO/Rh blood group determination via agglutination detection.
Main Results:
- The pressure balancing bypass effectively diminished pressure differences, enabling backflow-free liquid merging.
- The device successfully mixed aqueous dye solutions, with gravity's effect on pressure difference studied.
- Blood typing assays showed a consistent 10% longer filling time for agglutinated samples, confirming assay performance.
Conclusions:
- The developed micromixing device is robust, portable, and insensitive to backflow.
- The device shows significant potential for various agglutination-based assays, including blood typing.
- This technology is well-suited for point-of-care and lab-on-a-chip applications.
