A microengineered vascularized bleeding model that integrates the principal components of hemostasis

Area of Science:

• Biomedical Engineering
• Hematology
• Microfluidics

Background:

• Hemostasis is a complex process involving multiple blood components and forces.
• Existing assays evaluate only limited aspects of hemostasis.
• A comprehensive in vitro model is needed to study hemostasis comprehensively.

Purpose of the Study:

• To develop and validate a microfluidic system for simulating vascular injury and measuring in vitro bleeding time.
• To investigate the roles of various hemostasis components in clot formation and stability.
• To gain insights into unresolved hematologic issues using a comprehensive mechanical injury model.

Main Methods:

• Development of an endothelialized microfluidic system with a microengineered pneumatic valve for controlled vascular injury.
• Perfusion of whole blood to visualize hemostatic plug formation and measure in vitro bleeding time.
• Quantitative analysis of anti-platelet agent effects, von Willebrand factor function, hemophilia A blood behavior, and endothelial phosphatidylserine's role.

Main Results:

• Demonstrated the effect of anti-platelet agents on clot contraction and hemostatic plug formation.
• Confirmed the essential role of von Willebrand factor in hemostasis under high shear conditions.
• Observed unstable hemostatic plug formation and altered fibrin architecture in hemophilia A blood.
• Highlighted the significance of endothelial phosphatidylserine in hemostasis.

Conclusions:

• The developed microfluidic bleeding model provides a versatile platform for comprehensive hemostasis assessment.
• The model offers valuable insights into the complex interactions governing hemostatic plug formation.
• This technology has significant clinical utility for studying hemostatic disorders and evaluating therapeutic interventions.