A simple method for activating the platelets used in microfluidic platelet aggregation tests: Stirring-induced...

Area of Science:

• Biomedical Engineering
• Hematology
• Fluid Dynamics

Background:

• High shear stress is crucial for platelet activation and thrombus formation.
• Previous work established microfluidic systems for platelet function analysis.
• Understanding shear-induced platelet behavior is vital for thrombosis research.

Purpose of the Study:

• To investigate the impact of stirring on shear-induced platelet activation and aggregation.
• To analyze the fluid dynamics, including secondary flows, generated by a rotating stirrer.
• To determine the critical shear rate for maximum platelet aggregation.

Main Methods:

• Utilized a chamber system with a rotating stirrer to induce shear flow.
• Characterized rotational and radial secondary flows within the chamber.
• Quantified platelet aggregation at varying shear rates and stirrer designs.
• Confirmed findings using a microfluidic system for platelet aggregation testing.

Main Results:

• Rotating stirrers generate both rotational shear flow and radial secondary flow, enhancing mixing.
• Controlled shear stress activates platelets, with maximum aggregation occurring at 3100 s⁻¹.
• Wider stirrers significantly reduced the time to reach maximum platelet aggregation (30s vs 180s).
• Radial secondary flow promoted homogenous platelet activation across the chamber.

Conclusions:

• The chamber system with a rotating stirrer effectively stimulates platelets via shear stress.
• This system provides a controllable method for inducing and studying platelet aggregation.
• Findings confirm the mechanism of stirring-induced platelet activation and aggregation.