Dynamics of a Spherical Capsule in a Near-Wall Shear Flow

2012 ◽  
Author(s):  
Stephanie Nix ◽  
Yohsuke Imai ◽  
Daiki Matsunaga ◽  
Takuji Ishikawa ◽  
Takami Yamaguchi
Keyword(s):  
Blood Cells ◽  
Vessel Wall ◽  
White Blood Cells ◽  
Blood Vessel Wall ◽  
Lateral Migration ◽  
Free Layer ◽  
A Cell ◽  
Spherical Capsule ◽  
Migration Of Cells ◽  
Cell Free Layer

Lateral migration of cells in the bloodstream is affected by the material properties of the constituent cells. In blood vessels, red blood cells migrate to the center of the vessel, leading to the formation of a cell-free layer near the vessel wall; on the other hand, less deformable cells such as white blood cells and platelets are more likely to be found near the blood vessel wall. [1]

Analysis of mechanisms for platelet near-wall excess under arterial blood flow conditions

2011 ◽  
Vol 676 ◽  
pp. 348-375 ◽  
Author(s):  
L. CROWL ◽  
A. L. FOGELSON
Keyword(s):  
Blood Cell ◽  
Red Blood Cells ◽  
Red Blood Cell ◽  
Blood Cells ◽  
Vessel Wall ◽  
Arterial Blood Flow ◽  
Free Layer ◽  
Flow Conditions ◽  
Cell Free Layer ◽  
Near Wall

The concentration of platelets near the blood vessel wall is important because platelets survey the condition of the vessel wall and respond to injuries to it. Under arterial flow conditions, platelets are non-uniformly distributed across the vessel lumen and have a high concentration within a few microns of the vessel wall. This is believed to be a consequence of the complex motion of red blood cells which constitute a large fraction of the blood's volume. We use a novel lattice Boltzmann-immersed boundary method to simulate, in two dimensions, the motion of dense red blood cell suspensions and their effect on platelet-sized particles. We track the development of a red blood cell-free layer near the wall and the later development of the platelet near-wall excess. We find that the latter develops more quickly at high wall shear rates and that the magnitude of the excess and its proximity to the wall are dependent on haematocrit. Treating the simulation data as if it were generated by a drift–diffusion process, we find that the effective lateral platelet diffusivity depends strongly on lateral position; it has a magnitude of order of 10−6 cm2 s−1 over much of the lumen but drops to almost zero close to the wall. This large effective diffusivity over the core of the lumen combined with reduced space for platelets in this region because of the inward migration of red blood cells largely but not completely accounts for the observed platelet-concentration profiles. We present evidence for a highly localized red blood cell-induced platelet drift at the edge of the red cell-free layer and suggest a physical mechanism that may generate it.

scholarly journals Emergent cell-free layer asymmetry and biased haematocrit partition in a biomimetic vascular network of successive bifurcations

Soft Matter ◽  
2021 ◽  
Author(s):  
Qi Zhou ◽  
Joana Fidalgo ◽  
Miguel Bernabeu ◽  
Mónica S.N. Oliveira ◽  
Timm Krüger
Keyword(s):  
Red Blood Cells ◽  
Human Body ◽  
Blood Cells ◽  
Soft Matter ◽  
Vascular Network ◽  
Free Layer ◽  
Cell Free Layer

Blood is a vital soft matter, and its normal circulation in the human body relies on the distribution of red blood cells (RBCs) at successive bifurcations. Understanding how RBCs are...

scholarly journals Effect of Cytoplasmic Viscosity on Red Blood Cell Migration in Small Arteriole-level Confinements

2019 ◽  
Author(s):  
Amir Saadat ◽  
Christopher J. Guido ◽  
Eric S. G. Shaqfeh
Keyword(s):  
Blood Cell ◽  
Red Blood Cells ◽  
Red Blood Cell ◽  
Blood Cells ◽  
Large Scale ◽  
Volume Fraction ◽  
Free Layer ◽  
Channel Size ◽  
Viscosity Contrast ◽  
Cell Free Layer

The dynamics of red blood cells in small arterioles are important as these dynamics affect many physiological processes such as hemostasis and thrombosis. However, studying red blood cell flows via computer simulations is challenging due to the complex shapes and the non-trivial viscosity contrast of a red blood cell. To date, little progress has been made studying small arteriole flows (20-40μm) with a hematocrit (red blood cell volume fraction) of 10-20% and a physiological viscosity contrast. In this work, we present the results of large-scale simulations that show how the channel size, viscosity contrast of the red blood cells, and hematocrit affect cell distributions and the cell-free layer in these systems. We utilize a massively-parallel immersed boundary code coupled to a finite volume solver to capture the particle resolved physics. We show that channel size qualitatively changes how the cells distribute in the channel. Our results also indicate that at a hematocrit of 10% that the viscosity contrast is not negligible when calculating the cell free layer thickness. We explain this result by comparing lift and collision trajectories of cells at different viscosity contrasts.

Deformation of White Blood Cells Firmly Adhered to Endothelium

2012 ◽  
Author(s):  
Alex C. Szatmary ◽  
Rohan J. Banton ◽  
Charles D. Eggleton
Keyword(s):  
Blood Cells ◽  
Fluid Shear Stress ◽  
White Blood Cells ◽  
Infection Site ◽  
Hydrodynamic Load ◽  
Fluid Shear ◽  
Cell Deformability ◽  
Selectin Ligands ◽  
A Cell ◽  
Bond Kinetics

Circulating white blood cells adhere to endothelium near an infection site; this occurs because infection causes ligands to be expressed on activated endothelium. Initially, a white blood cell rolls on the substrate, but eventually forms a firm adhesion, allowing it to crawl through the endothelial layer toward the infected tissue. A computational model of bond kinetics, cell deformability, and fluid dynamics was used to model the forces experienced by a cell during this process. The cell was modeled as a fluid-filled membrane; on its surface were hundreds of deformable microvilli—little fingers, ruffles in the white blood cell’s wrinkly membrane. These microvilli were deformable and their tips were decorated with PSGL-1 chemical receptors which bound to P-selectin ligands on the surface. Softer cells and cells subjected to higher fluid shear stress deformed more, and having more contact area, they formed more bonds and were able to resist more hydrodynamic load.

scholarly journals Blood Particulate Analogue Fluids: A Review

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2451
Author(s):  
Samir Hassan Sadek ◽  
Manuel Rubio ◽  
Rui Lima ◽  
Emilio José Vega
Keyword(s):  
Mechanical Properties ◽  
Blood Cells ◽  
Sample Storage ◽  
Free Layer ◽  
Dynamic Flow ◽  
Microcirculatory System ◽  
Flow Phenomena ◽  
Cell Free Layer ◽  
Made In

Microfluidics has proven to be an extraordinary working platform to mimic and study blood flow phenomena and the dynamics of components of the human microcirculatory system. However, the use of real blood increases the complexity to perform these kinds of in vitro blood experiments due to diverse problems such as coagulation, sample storage, and handling problems. For this reason, interest in the development of fluids with rheological properties similar to those of real blood has grown over the last years. The inclusion of microparticles in blood analogue fluids is essential to reproduce multiphase effects taking place in a microcirculatory system, such as the cell-free layer (CFL) and Fähraeus–Lindqvist effect. In this review, we summarize the progress made in the last twenty years. Size, shape, mechanical properties, and even biological functionalities of microparticles produced/used to mimic red blood cells (RBCs) are critically exposed and analyzed. The methods developed to fabricate these RBC templates are also shown. The dynamic flow/rheology of blood particulate analogue fluids proposed in the literature (with different particle concentrations, in most of the cases, relatively low) is shown and discussed in-depth. Although there have been many advances, the development of a reliable blood particulate analogue fluid, with around 45% by volume of microparticles, continues to be a big challenge.

scholarly journals Individual Motions of Red Blood Cells in High-Hematocrit Blood Flowing in a Microchannel With Complex Geometries

2009 ◽  
Author(s):  
T. Ishikawa ◽  
H. Fujiwara ◽  
N. Matsuki ◽  
R. Lima ◽  
Y. Imai ◽  
...  
Keyword(s):  
Flow Field ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Complex Geometries ◽  
Free Layer ◽  
Homogeneous Fluid ◽  
Small Vessels ◽  
Small Channel ◽  
Multiphase Fluid ◽  
Cell Free Layer

Blood flow in a microchannel with complex geometries has been investigated to develop biomedical microdevices (e.g. Faivre et al., 2006) or to understand pathology in small vessels, such as lacunar infarcts. In a small channel, say 100 μm in diameter, the blood is no longer assumed to be a homogeneous fluid because the size of the red blood cells (RBCs) cannot be neglected compared to the generated flow field (the diameter of a RBC is about 8 μm). In such a case, we must treat the blood as a multiphase fluid, and investigate the motion of individual cells in discussing the flow field. In this study, we investigated the motion of RBCs in a microchannel with stenosis or bifurcation using a confocal micro-PTV system. We measured individual trajectories of RBCs under high Hct conditions (up to 20%), when the interactions between RBCs become significant. We discuss the effect of Hct on the flow field and cell-free layers, as well as the effect of deformability of RBCs on the cell-free layer thickness by hardening RBCs using a glutaraldehyde treatment.

scholarly journals MOTION OF RED BLOOD CELLS AND CELL FREE LAYER DISTRIBUTION IN A STENOSED MICROCHANNEL

2008 ◽  
Vol 41 ◽  
pp. S390
Author(s):  
Hiroki FUJIWARA ◽  
Takuji ISHIKAWA ◽  
Rui LIMA ◽  
Yohsuke IMAI ◽  
Noriaki MATSUKI ◽  
...  
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Free Layer ◽  
Cell Free Layer

Development of margination of platelet-sized particles in red blood cell suspensions flowing through Y-shaped bifurcating microchannels

Biorheology ◽  
2021 ◽  
Vol 57 (2-4) ◽  
pp. 101-116
Author(s):  
Masako Sugihara-Seki ◽  
Tenki Onozawa ◽  
Nozomi Takinouchi ◽  
Tomoaki Itano ◽  
Junji Seki
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Vessel Wall ◽  
Flow Direction ◽  
Spherical Particles ◽  
Free Layer ◽  
Low Concentrations ◽  
Asymmetric Distributions ◽  
Cell Free Layer

BACKGROUND: In the blood flow through microvessels, platelets exhibit enhanced concentrations in the layer free of red blood cells (cell-free layer) adjacent to the vessel wall. The motion of platelets in the cell-free layer plays an essential role in their interaction with the vessel wall, and hence it affects their functions of hemostasis and thrombosis. OBJECTIVE: We aimed to estimate the diffusivity of platelet-sized particles in the transverse direction (the direction of vorticity) across the channel width in the cell-free layer by in vitro experiments for the microchannel flow of red blood cell (RBC) suspensions containing platelet-sized particles. METHODS: Fluorescence microscope observations were performed to measure the transverse distribution of spherical particles immersed in RBC suspensions flowing through a Y-shaped bifurcating microchannel. We examined the development of the particle concentration profiles along the flow direction in the daughter channels, starting from asymmetric distributions with low concentrations on the inner side of the bifurcation at the inlet of the daughter channels. RESULTS: In daughter channels of 40 μm width, reconstruction of particle margination revealed that a symmetric concentration profile was attained in ∼30 mm from the bifurcation, independent of flow rate. CONCLUSIONS: We presented experimental evidence of particle margination developing in a bifurcating flow channel where the diffusivity of 2.9-μm diameter particles was estimated to be ∼40 μm2/s at a shear rate of 1000 s−1 and hematocrit of 0.2.

Computational Modeling of Human Leukocyte

2002 ◽  
Author(s):  
Saikrishna Marella ◽  
H. S. Udaykumar
Keyword(s):  
Blood Flow ◽  
Blood Cells ◽  
Vessel Wall ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
White Blood Cells ◽  
Human Leukocyte ◽  
Spherical Shape ◽  
First Line ◽  
Circulating Cells

Leukocytes (white blood cells) occupy only about 1/600th of blood by volume [1,2]. However, in view of the fact that leukocytes are larger and much stiffer than red blood cells, their presence is critical to the fluid mechanics of blood flow in the peripheral blood vessels, where the vessel diameters are comparable to those of the cells. These circulating cells must navigate through narrow micro-capillaries and recover to their undeformed spherical shape. Leukocytes act as the first line of defense in fighting disease. Leukocyte recruitment for this role involves a series of steps, including margination to vessel walls, rolling, adhesion to the endothelium, activation and locomotion and extravasation through the vessel wall to the tissue, which is afflicted by the trauma. Because the leukocyte is stiff and difficult to deform it can plug occluded micro-capillaries, leading to events such as ischemic stroke. Furthermore, leukocyte agglomeration and subsequent emolization can have serious consequences in patients under trauma, causing organ loss or even fatalities due to ischemia reperfusion injury. In these various scenarios, the rheological behavior, i.e. the physics of deformation and recovery of leukocytes under a wide variety of imposed flows, is essential.

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