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Traffic of leukocytes in microfluidic channels with rectangular and rounded cross-sections
Xiaoxi Yang1, Omid Forouzan, Jennie M Burns
1Department of Biomedical Engineering, Tulane University, New Orleans, LA 70118, USA.
Lab on a Chip
|August 18, 2011
Summary
Microchannel cross-sectional geometry significantly alters leukocyte traffic at bifurcations. Rounded channels promote entry into smaller branches, unlike rectangular channels, impacting microcirculation models.
Area of Science:
- Biomedical Engineering
- Microfluidics
- Hemodynamics
Background:
- Leukocyte traffic in microvascular networks influences blood flow dynamics, inflammation, and atherosclerosis.
- Recent efforts focus on creating artificial microvascular networks with realistic, rounded cross-sections.
Purpose of the Study:
- To investigate the impact of microchannel cross-sectional geometry (rectangular vs. rounded) on leukocyte traffic through a non-symmetrical bifurcation.
- To compare leukocyte distribution in 30 μm and 50 μm daughter branches under different cross-sectional conditions.
Main Methods:
- Fabrication of identical non-symmetrical bifurcations (50 μm to 30 μm and 50 μm branches) using photolithography.
- Modification of rectangular microchannels to rounded cross-sections using liquid polydimethylsiloxane (PDMS)/air bubble injection.
- Observation and quantification of leukocyte traffic in human whole blood flowing through the bifurcations.
Main Results:
- In rounded channels, approximately two-thirds of leukocytes entered the 30 μm branch.
- In rectangular channels, most leukocytes continued into the 50 μm branch.
- Differences attributed to leukocyte margination in rectangular channels and geometric hindrance at the bifurcation entrance.
Conclusions:
- Microchannel cross-sectional geometry critically affects leukocyte trajectories at bifurcations.
- Microfluidic models require geometries closely mimicking physiological conditions for accurate microcirculation studies.
