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Size-Based Sorting of Emulsion Droplets in Microfluidic Channels Patterned with Laser-Ablated Guiding Tracks
Ateeq Ur Rehman, Umut C Coskun1, Zeeshan Rashid2
1Department of Mechanical Engineering , Istanbul Technical University , 34437 Gumussuyu , Istanbul , Turkey.
Analytical Chemistry
|January 7, 2020
Summary
This study presents a microfluidic method to autonomously sort emulsion droplets by size using a laser-ablated track. This high-throughput technique enables precise separation for various microfluidic applications.
Area of Science:
- Microfluidics
- Fluid Dynamics
- Surface Engineering
Background:
- Microfluidic devices enable precise control over small fluid volumes.
- Sorting droplets by size is crucial for applications in diagnostics and synthesis.
- Existing droplet sorting methods often lack high throughput or autonomous operation.
Purpose of the Study:
- To develop an autonomous, high-throughput microfluidic system for sorting emulsion droplets based on size.
- To investigate the physical mechanisms governing droplet trajectory and separation in a microfluidic channel with a guiding track.
- To demonstrate the efficacy of the developed technique for separating droplets of different sizes and origins.
Main Methods:
- Fabrication of a microfluidic Hele-Shaw channel with a shallow, inclined guiding track using femtosecond laser ablation.
- Generation and manipulation of aqueous droplets in olive oil within the microfluidic channel.
- Systematic study of droplet size and velocity effects on trajectory using experimental observation and computational fluid dynamics (CFD) simulations.
- Analysis of droplet interaction with the guiding track, considering confinement forces, fluid drag, and wall friction.
Main Results:
- Demonstrated autonomous, size-based sorting of emulsion droplets flowing concurrently in a microfluidic channel.
- Identified that droplet trajectory differences arise from the radius-dependent scaling of confinement force, drag, and friction.
- Showcased stable droplet guiding, enhanced by wider tracks, and analyzed trajectory sensitivity to flow conditions.
- Achieved complete separation of droplets from fused streams from unfused droplets.
Conclusions:
- The developed laser-ablated guiding track provides an effective mechanism for high-throughput, autonomous droplet sorting in microfluidics.
- The findings offer a deeper understanding of droplet dynamics within microscale guiding structures.
- This technique holds significant potential for advancing analytical and preparative microfluidic protocols.
