Extensional flow-based assessment of red blood cell deformability using hyperbolic converging microchannel

Area of Science:

• Biophysics
• Microfluidics
• Hematology

Background:

• Red blood cell (RBC) deformability impacts microcirculation and disease diagnosis (e.g., malaria, sepsis).
• Conventional methods often overlook extensional flow, focusing on shear flow for cell deformability measurements.
• Existing models for blood damage in artificial organs primarily consider shear flow, potentially missing critical extensional flow effects.

Purpose of the Study:

• To introduce a novel approach for assessing red blood cell deformability using extensional flow.
• To design and utilize a hyperbolic converging microchannel for studying RBCs in extensional flow.
• To compare the efficacy of extensional flow versus shear flow in inducing RBC deformation.

Main Methods:

• Development of a hyperbolic converging microchannel to generate controlled extensional flow.
• Continuous monitoring of red blood cell deformation within the extensional flow region.
• Quantification of cell deformation using a Deformation Index under varying flow conditions (extensional vs. shear).

Main Results:

• Extensional flow demonstrated significantly higher RBC deformation (Deformation Index = 0.51 at 3.0 Pa) compared to shear flow (Deformation Index = 0.29 at 3.0 Pa).
• The new method successfully detected heat-induced differences in RBC deformability.
• Experiment time was notably reduced compared to conventional techniques.

Conclusions:

• Extensional flow is a more potent factor in RBC deformation than shear flow, highlighting limitations in current blood damage models.
• The developed microfluidic platform provides a sensitive tool for studying RBC deformability under extensional flow.
• This approach is expected to advance understanding of RBCs' role in various diseases and clinical conditions.