A passive microfluidic device for plasma extraction from whole human blood

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Microfluidics

Background:

• Plasma extraction from whole blood is crucial for diagnostics and research.
• Existing methods can be complex, time-consuming, or require active components.
• Microfluidic approaches offer potential for miniaturized, efficient blood processing.

Purpose of the Study:

• To develop and validate novel microfluidic devices for continuous and passive plasma extraction.
• To investigate the underlying principles of red blood cell migration and cell-free layer expansion in microchannels.
• To optimize device geometry for maximizing plasma extraction efficiency.

Main Methods:

• Design and fabrication of microfluidic devices featuring geometric singularities (enlargements, cavities).
• Computational fluid dynamics (CFD) to analyze flow patterns and cell behavior.
• Experimental validation using whole human blood, assessing plasma extraction rates.
• Iterative optimization of device design parameters.

Main Results:

• Demonstrated passive plasma extraction driven by red blood cell lateral migration.
• Identified geometric singularities as key elements for expanding the cell-free layer.
• Achieved a maximum plasma extraction yield of 17.8% with a 1:20 blood dilution at 100 µL/min flow rate.
• Experimental results aligned with CFD predictions of flow dynamics.

Conclusions:

• The proposed microfluidic devices enable efficient, continuous, and passive plasma separation from whole blood.
• The designs leverage fundamental fluid dynamics principles for cell manipulation.
• These devices represent a significant advancement for point-of-care diagnostics and biomedical research applications requiring plasma.