Vacuum Flow Focusing Microfluidics to Study Blood Cell Dynamics under Shear Gradient Aggregation Mechanism

This paper reports on the development of a microfluidic platform to study mass transport behaviour of blood cells at micro-scale stenosis where local strain-rate micro-gradients trigger platelet aggregation. We present the design, fabrication and blood testing of a microfluidic device that incorporates symmetric or asymmetric flow focusing using a single pressure driver to study the hemodynamic variables promoting platelet aggregation at defined micro-contraction geometries. The thickness of the different streams can be controlled by changing the hydraulic resistance of the inlet feeder channels and by controlling the hydrostatic pressure of the reservoirs. This platform will facilitate the study of the role of mass transport phenomena in platelet thrombus formation and will lead to a greater understanding of the mechanism(s) underlying shear-gradient dependent discoid platelet aggregation in the context of cardiovascular diseases such as acute coronary syndromes and ischemic stroke.