The Margination of Particles in Areas of Constricted Blood Flow

Abstract

Stroke is a leading cause of death globally and is caused by stenoses, abnormal narrowings of blood vessels. Recently, there has been an increased interest in shear-activated particle clusters for the treatment of stenosis, but there is a lack of literature investigating the impact of different stenosis geometries on particle margination. Margination refers to the movement of particles toward the blood vessel wall and is desirable for drug delivery. The current study investigated ten different geometries and their effects on margination. Microfluidic devices with a constricted area were fabricated to mimic a stenosed blood vessel with different extent of occlusion, constricted length, and eccentricity (gradualness of the constriction and expansion). Spherical fluorescent particles with a diameter of 2.11 μm were suspended in blood and tracked as they moved into, through, and out of the constricted area. A margination parameter, M, was used to quantify margination based on the particle distribution after velocity normalization. Experimental results suggested that a constriction leads to an enhanced margination, whereas an expansion is responsible for a decrease in margination. Further, margination was found to increase with increasing percent occlusion and constriction length, likely a result of higher shear rate and longer residence time, respectively. Margination decreases as the stenosis geometry becomes more gradual (eccentricity increases) with the exception of a sudden constriction/expansion geometry. The findings demonstrate the importance of geometric effects on margination and call for detailed numerical modeling and geometric characterization of the stenosed areas to fully understand the underlying physics.

Red Blood Cells: Chasing Interactions

“…Platelets exhibit a phenomenon called platelet margination or lateral drift, in which the concentration of platelets is highest near the vessel wall (Namdee et al, 2013; Vahidkhahb et al, 2014). This seems to be the result of an interaction with RBC (Vahidkhah et al, 2013; Carboni, 2017). When a platelet comes across a RBC, either a crossing or a turning interaction occurs.…”

Computational modeling of blood component transport related to coronary artery thrombosis in Kawasaki disease

“…Therefore, based on these data, we did not expect significant margination effect in this study due to the low shear rates observed in KD aneurysms (100 s −1 ) from our hemodynamic simulations and the typical length of coronary arteries. In addition, geometry changes such as expansions or constrictions have been reported to significantly effect particle margination [60]. For these reasons, here we considered the full 3D fluid domain in our calculations of platelet activation and platelet accumulation.…”

Numerical and experimental analysis of a high-throughput blood plasma separator for point-of-care applications

“…These products are used as biomarkers, indicating the presence of certain diseases in an individual. [1][2][3] However, blood cells sometimes interfere in the biochemical readout of the results. Hence, plasma cell separation is essential in disease diagnostics.…”

“…These systems must be portable, but also accurate, reliable, rugged and well suited to the medical and social contexts of the developing world. [1,4] The microfluidic plasma-separation methods have the capability of direct connection to miniaturized sensors. Thus, they can create miniaturized POC or can be embedded in small machines for screening a large number of people in a short period (i.e.…”