Investigation of red blood cell partitioning in an in vitro microvascular bifurcation

Abstract

There is a long history of research examining red blood cell (RBC) partitioning in microvasculature bifurcations. These studies commonly report results describing partitioning that exists as either regular partitioning, which occurs when the RBC flux ratio is greater than the bulk fluid flowrate ratio, or reverse partitioning when the RBC flux ratio is less than or equal to that of the bulk fluid flowrate. This paper presents a study of RBC partitioning in a single bifurcating microchannel with dimensions of 6 to 16 μm, investigating the effects of hematocrit, channel width, daughter channel flowrate ratio, and bifurcation angle. The erythrocyte flux ratio, N*, manifests itself as either regular or reverse partitioning, and time‐dependent partitioning is much more dynamic, occurring as both regular and reverse partitioning. We report a significant reduction in the well‐known sigmoidal variation of the erythrocyte flux ratio (N*) versus the volumetric flowrate ratio (Q*), partitioning behavior with increasing hematocrit in microchannels when the channel dimensions are comparable with cell size. RBCs “lingering” or jamming at the bifurcation were also observed and quantified in vitro. Results from trajectory analyses suggest that the RBC position in the feeder channel strongly affects both partitioning and lingering frequency of RBCs, with both being significantly reduced when RBCs flow on streamlines near the edge of the channel as opposed to the center of the channel. Furthermore, our experiments suggest that even at low Reynolds number, partitioning is affected by the bifurcation angle by increasing cell–cell interactions. The presented results provide further insight into RBC partitioning as well as perfusion throughout the microvasculature.

Glomerular microcirculation: Implications for diabetes, preeclampsia, and kidney injury

“…In addition, the authors emphasize that even minor changes in capillary geometry result in changes in the flow field and RBC distribution. In microfabricated channels perfused with RBCs, Pskowski et al 39 observed regular and reverse partitioning; RBC “lingering” or jamming at the bifurcation; and the unequal distribution dependent on bifurcation angle. More recently, Clavica et al 40 using symmetric and asymmetric microchannels confirmed RBC's bias in entering branches at bifurcations according to Zweifach–Fung self‐sustaining oscillatory effect and inversion of Zweifach–Fung effect with increasing flow velocity.…”

Red blood cell lingering modulates hematocrit distribution in the microcirculation

“…Partitioning of red blood cells (RBCs) through bifurcations of blood vessels determines how the oxygen is delivered to tissues and organs. Early studies have shown that this partitioning is a complex phenomenon ( 1 , 2 , 3 , 4 ) and, since then, it has been an area of intensive research, attracting a wide range of experimental ( 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ) and numerical ( 14 , 15 , 16 , 17 , 18 , 19 , 20 ) studies. More accurately, vessels with a higher flow rate tend to collect an even higher proportion of RBCs.…”

Influence of storage and buffer composition on the mechanical behavior of flowing red blood cells

“…In parallel, several other studies where the mechanical interplay between cells and flow is crucial only used the classical phosphate-buffered-saline solution as a suspending fluid, which raises the question of biases due to sedimentation (12,(56)(57)(58)(59)(60)(61), in particular for those considering aggregating cells (23,(62)(63)(64). This diversity in methodology leads to question the reliability of comparisons of results obtained by different research groups working with different suspending media.…”