Quantifying Embolism: Label-Free Volumetric Mapping of Thrombus Structure and Kinesis in a Microfluidic System with Optical Holography

Embolization of thrombotic material may lead to acute events such as ischemia and myocardial infarction. The embolus is the physical detachment from a primary thrombus that has developed under fluid shear rates. The physical characteristics (surface area coverage, volume, mass, and packing density) of a thrombus influence the overall flow dynamics of an occluding blood vessel. Here, the effectiveness of holographic quantitative phase microscopy (QPM) in identifying multiple morphological parameters of a thrombus (volume, surface area, and height) formed over collagen-coated microfluidic channels by exerting a range of shear rates with anticoagulated platelet-rich plasma (PRP) and whole blood is demonstrated. QPM enables the recording of entire thrombus volumes in real-time using PRP and observed both growth and contraction trends of thrombi, without need for biochemical labeling. The process of emboli detachment in a microfluidic channel under pathophysiological shear rates (7500 and 12 500 s⁻¹) is quantified. Rapid and direct quantification of an embolizing thrombus can enable the study of events during undesirable vessel occlusion and lead to targeting and early diagnosis of acute coronary and venous events.