Study of erythrocyte aggregation at pulsatile flow conditions with backscattering analysis

Area of Science:

• Biomedical Engineering
• Hematology
• Fluid Dynamics

Background:

• Red blood cell (RBC) aggregation is crucial for blood rheology but challenging to study under physiological pulsatile flow.
• Existing methods struggle with simulating realistic flow conditions and accurately detecting RBC aggregation.

Purpose of the Study:

• To develop a microfluidic system capable of generating physiologically relevant cyclic pulsatile flow.
• To investigate and quantify RBC aggregation dynamics under these pulsatile flow conditions.
• To assess the utility of critical shear stress as an indicator of RBC aggregation in pulsatile flow.

Main Methods:

• A novel microfluidic device was engineered to produce cyclic pulsatile flow within a microchannel.
• Backscattered light signals from human blood samples were continuously monitored over time.
• RBC aggregation was analyzed by measuring critical shear stress under varying flow conditions, including control, normal RBCs, and hardened RBCs in different media.

Main Results:

• The microfluidic system successfully generated cyclic pulsatile flow for RBC aggregation studies.
• Critical shear stress values for control and hardened RBCs in plasma under pulsatile flow closely matched those under single-pulse conditions.
• The measured critical shear stress demonstrated remarkable consistency throughout the entire pulsatile flow cycles.

Conclusions:

• Critical shear stress is a reliable and observable parameter in cyclic pulsatile flow.
• This parameter serves as a significant index for characterizing in-vivo pulsatile blood flow rheology.
• The developed microfluidic system offers a viable platform for future research into blood flow dynamics.