Nonuniform red cell distribution in 20 to 100 μm bifurcations

Fenton, Bruce M.; Carr, Russell T.; Cokelet, Giles R.

doi:10.1016/0026-2862(85)90010-x

Cited by 146 publications

(100 citation statements)

References 27 publications

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“…2,8,10,15,37,[45][46][47] On one hand, despite the development of microfluidics in the last decade, in vitro experiments have not yet permitted to explore phase separation in bifurcations with branches of characteristic size smaller than 20 lm nor in asymmetric channels with at least one branch smaller (both in depth and width) than the other ones. In addition, "room-sized" experimental models, designed according to the principles of kinematic and dynamic similarity, cannot reproduce the complex rheological properties of RBCs.…”

Section: Introductionmentioning

confidence: 99%

“…This should ultimately allow a better understanding of the physics at play and a parametrical characterization of the phase-separation effect in steady state, potentially improving the phenomenological description of Pries et al 33,37 The aim of the present paper is to present the experimental methodologies and measurement techniques developed for that purpose, especially in the case of channels of capillary size or slightly larger (typically below 20 lm), including asymmetric bifurcations, in the full physiological hematocrit range. The main originalities of the experiment are the following: first, we design polydimethylsiloxane (PDMS) micro-bifurcations made of square channels with different sizes, while most of the recent previous studies used bifurcations made of rectangular channels with unique depth, 15,45,47 which are easier to fabricate; 48 second, we are interested in regimes which are seldom studied (moderately to highly concentrated RBC suspension flows in small micro-channels), while in most previous studies, channels with sizes superior or equal to 20 lm have been used; 2,8,10,15,[45][46][47] and third, we simultaneously aim at a rigorous control of the experimental conditions, including the possibility of varying independently the inlet hematocrit and the flow rate ratio between both daughter branches, and at an in situ quantitative measurement of the flow parameters. This is extremely challenging in the considered flow regimes and necessitates a combination of various metrologies, including the comparison with reference measurements, in order to validate the results.…”

Section: Introductionmentioning

confidence: 99%

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Going beyond 20 μm-sized channels for studying red blood cell phase separation in microfluidic bifurcations

et al. 2016

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Despite the development of microfluidics, experimental challenges are considerable for achieving a quantitative study of phase separation, i.e., the non-proportional distribution of Red Blood Cells (RBCs) and suspending fluid, in microfluidic bifurcations with channels smaller than 20 lm. Yet, a basic understanding of phase separation in such small vessels is needed for understanding the coupling between microvascular network architecture and dynamics at larger scale. Here, we present the experimental methodologies and measurement techniques developed for that purpose for RBC concentrations (tube hematocrits) ranging between 2% and 20%. The maximal RBC velocity profile is directly measured by a temporal cross-correlation technique which enables to capture the RBC slip velocity at walls with high resolution, highlighting two different regimes (flat and more blunted ones) as a function of RBC confinement. The tube hematocrit is independently measured by a photometric technique. The RBC and suspending fluid flow rates are then deduced assuming the velocity profile of a Newtonian fluid with no slip at walls for the latter. The accuracy of this combination of techniques is demonstrated by comparison with reference measurements and verification of RBC and suspending fluid mass conservation at individual bifurcations. The present methodologies are much more accurate, with less than 15% relative errors, than the ones used in previous in vivo experiments. Their potential for studying steady state phase separation is demonstrated, highlighting an unexpected decrease of phase separation with increasing hematocrit in symmetrical, but not asymmetrical, bifurcations and providing new reference data in regimes where in vitro results were previously lacking. Published by AIP Publishing. [http://dx

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Going beyond 20 μm-sized channels for studying red blood cell phase separation in microfluidic bifurcations

et al. 2016

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“…Also, it has been highlighted to accurately predict drug carrier distribution in the microvasculature [12][13][14][15][16][17][18]. For utilizing the plasma skimming to new applications in vitro and in vivo, it is crucial to quantitatively predict the redistribution of RBCs and plasma at bifurcations.From the early 70s, several experiments for quantifying the plasma skimming were performed [2,[19][20][21][22][23] In this paper, we aim to mathematically model fractional blood flow in a simple and generalized manner in order to computationally study its significance in plasma skimming, and also to accurately predict plasma skimming in the microvasculature. For this task, a recently developed plasma skimming model [26] is taken, and extended to take into account the effect of fractional blood flow.…”

mentioning

confidence: 99%

“…From the early 70s, several experiments for quantifying the plasma skimming were performed [2,[19][20][21][22][23] In this paper, we aim to mathematically model fractional blood flow in a simple and generalized manner in order to computationally study its significance in plasma skimming, and also to accurately predict plasma skimming in the microvasculature. For this task, a recently developed plasma skimming model [26] is taken, and extended to take into account the effect of fractional blood flow.…”

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Effect of fractional blood flow on plasma skimming in the microvasculature

2017

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Although redistribution of red blood cells at bifurcated vessels is highly dependent on flow rate, it is still challenging to quantitatively express the dependency of flow rate in plasma skimming due to nonlinear cellular interactions. We suggest a plasma skimming model that can involve the effect of fractional blood flow at each bifurcation point. For validating the new model, it is compared with in vivo data at single bifurcation points, as well as microvascular network systems. In the simulation results, the exponential decay of plasma skimming parameter, M , along fractional flow rate shows the best performance in both cases.Red blood cells (RBCs) in microvessels are concentrated on the vessel core. Subsequently, a cell-free layer (CFL) with a few micrometer thickness is observed on the vessel wall. The CFL leads asymmetric redistribution of hematocrit at each bifurcation, called plasma skimming effect. As a continuous process of plasma skimming in microvascular networks, the average hematocrit in capillary beds is lower than the systemic hematocrit as reported in many previous studies [1][2][3][4][5][6][7][8]. Interestingly, the plasma skimming is recently revisited to develop new microchannels for detecting specific DNAs, proteins and cells by efficiently separating plasma from whole blood [9][10][11]. Also, it has been highlighted to accurately predict drug carrier distribution in the microvasculature [12][13][14][15][16][17][18]. For utilizing the plasma skimming to new applications in vitro and in vivo, it is crucial to quantitatively predict the redistribution of RBCs and plasma at bifurcations.From the early 70s, several experiments for quantifying the plasma skimming were performed [2,[19][20][21][22][23] In this paper, we aim to mathematically model fractional blood flow in a simple and generalized manner in order to computationally study its significance in plasma skimming, and also to accurately predict plasma skimming in the microvasculature. For this task, a recently developed plasma skimming model [26] is taken, and extended to take into account the effect of fractional blood flow. This new model is then validated with experimental data at single bifurcation level, and also at microvascular network level.While there are other plasma skimming models [25,27], the model developed by Gould and Linninger [26] is considered due to its easy extensibility. The model is as follows:where H is the hematocrit, M is the plasma skimming parameter, ζ is the hematocrit change coefficient due to plasma skimming, Q is the flow rate, A is the crosssectional area of each vessel, and subscript 0, 1, and 2 indicate the parent, and two daughter vessels, respectively. Specifically, the plasma skimming parameter M is related to the cross-sectional distribution of RBCs near bifurcation. Small M represents that RBCs are highly concentrated on the vessel core. In other words, plasma dominant region, or CFL, is developed on the near wall region. The two separated regions, expressed as RBCs and plasma areas, lead to strong...

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The distribution of freely suspended particles at microfluidic bifurcations

Roberts

Olbricht

2005

AIChE Journal

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Nonuniform red cell distribution in 20 to 100 μm bifurcations

Cited by 146 publications

References 27 publications

Going beyond 20 μm-sized channels for studying red blood cell phase separation in microfluidic bifurcations

Going beyond 20 μm-sized channels for studying red blood cell phase separation in microfluidic bifurcations

Effect of fractional blood flow on plasma skimming in the microvasculature

The distribution of freely suspended particles at microfluidic bifurcations

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