Micro Blood Flow-Resolved Rheometry

Area of Science:

• Biomedical Engineering
• Microfluidics
• Hematology

Background:

• Assessing blood properties like red blood cell (RBC) aggregation and viscosity is crucial.
• Existing microfluidic methods face challenges including dead-volume loss, RBC sedimentation, and flow rate control.

Purpose of the Study:

• To develop a novel microfluidic method for accurate RBC aggregation and blood viscosity measurement.
• To address limitations of previous techniques in microfluidic blood analysis.

Main Methods:

• A microfluidic chip with distinct channels for high (main) and low (aggregation) shear rates.
• A two-step blood delivery system using an air cavity for RBC aggregation and a syringe pump for viscosity measurements.
• Analysis of time-lapse image intensity and flow rate to determine RBC aggregation index and blood viscosity.

Main Results:

• Validated fluid viscosity measurements using glycerin solutions.
• Demonstrated the method's ability to detect differences in hematocrit and dextran concentrations.
• Successfully identified changes in heat-shocked RBCs, indicating sensitivity to cellular alterations.

Conclusions:

• The proposed microfluidic method offers accurate and reliable measurement of RBC aggregation and blood viscosity.
• This technique effectively overcomes common challenges in microfluidic blood analysis.
• The method is capable of detecting significant changes in RBCs and blood medium properties.