non-Newtonian Blood Flow Research Articles

AC electrokinetic induced non-Newtonian electrothermal blood flow in 3D microfluidic biosensor with ring electrodes for point-of-care diagnostics

Efficient pumping of whole blood is an essential task in biomedical engineering, especially for point-of-care diagnostics using lab-on-a-chip devices. Alternating current (AC) electrokinetics have been widely used for several different applications among which pumping fluids using the precisely controlled electric field without any moving mechanical parts is significant. Due to its high conductive characteristic, it is difficult to drive the blood flow using the AC electroosmosis phenomenon because the electric double layer is highly compressed. Fortunately, the AC electrothermal (ACET) phenomenon occurs due to the variation of temperature-dependent permittivity and conductivity caused by Joule heating effects or other heat sources making it powerful for driving high electrical conductivity physiological fluids in biomedical devices. Compared with Newtonian fluids like saline solutions or urine, the non-Newtonian rheological nature and AC frequency-dependent dielectric property of blood make its ACET driving mechanism more complicated and attractive. In this paper, ACET induced blood flow in the 3D microfluidic channel is modeled by the lattice Boltzmann method accelerated using graphics processor units. The Carreau-Yasuda model is applied to simulate the shear-thinning behavior of blood flow, and its electrothermal pumping efficiency is investigated with respect to the AC electrode configuration, AC voltage magnitude, and AC signal frequency by comparing it with the ACET pumping of Newtonian fluids using scaling law analysis. The results demonstrate that the ACET phenomenon is effective for pumping non-Newtonian whole blood flow in microfluidic devices with ring electrodes which will contribute to the point-of-care diagnostic of bacterial bloodstream infections or rapid detection of circulating tumor cells.

The Effect of Slip Velocity on Unsteady Peristalsis MHD Blood Flow through a Constricted Artery Experiencing Body Acceleration

In this analysis, we present a theoretical study to examine the combined effect of both slip velocity and periodic body acceleration on an unsteady generalized non-Newtonian blood flow through a stenosed artery with permeable wall. A constant transverse magnetic field is applied on the peristaltic flow of blood, treating it as an elastico-viscous, electrically conducting and incompressible fluid. Appropriate transformation methods are adopted to solve the unsteady non-Newtonian axially symmetric momentum equation in the cylindrical polar coordinate system with suitably prescribed conditions. To validate the applicability of the proposed analysis, analytical expressions for the axial velocity, fluid acceleration, wall shear stress and volumetric flow rate are computed and for having an adequate insight to blood flow behavior through a stenosed artery, graphs have been plotted with varying values of flow variables, to analyse the influence of the axial velocity, wall shear stress and volumetric flow rate of streaming blood.

A Formulation for Fluid-Structure Interactions in febio Using Mixture Theory.

Many physiological systems involve strong interactions between fluids and solids, posing a significant challenge when modeling biomechanics. The objective of this study was to implement a fluid-structure interaction (FSI) solver in the free, open-source finite element code FEBio, that combined the existing solid mechanics and rigid body dynamics solver with a recently developed computational fluid dynamics (CFD) solver. A novel Galerkin-based finite element FSI formulation was introduced based on mixture theory, where the FSI domain was described as a mixture of fluid and solid constituents that have distinct motions. The mesh was defined on the solid domain, specialized to have zero mass, negligible stiffness, and zero frictional interactions with the fluid, whereas the fluid was modeled as isothermal and compressible. The mixture framework provided the foundation for evaluating material time derivatives in a material frame for the solid and in a spatial frame for the fluid. Similar to our recently reported CFD solver, our FSI formulation did not require stabilization methods to achieve good convergence, producing a compact set of equations and code implementation. The code was successfully verified against benchmark problems from the FSI literature and an analytical solution for squeeze-film lubrication. It was validated against experimental measurements of the flow rate in a peristaltic pump and illustrated using non-Newtonian blood flow through a bifurcated carotid artery with a thick arterial wall. The successful formulation and implementation of this FSI solver enhance the multiphysics modeling capabilities in febio relevant to the biomechanics and biophysics communities.

Numerical simulation of two-phase non-Newtonian blood flow with fluid-structure interaction in aortic dissection

The behavior of blood cells and vessel compliance significantly influence hemodynamic parameters, which are closely related to the development of aortic dissection. Here the two-phase non-Newtonian model and the fluid-structure interaction (FSI) method are coupled to simulate blood flow in a patient-specific dissected aorta. Moreover, three-element Windkessel model is applied to reproduce physiological pressure waves. Important hemodynamic indicators, such as the spatial distribution of red blood cells (RBCs) and vessel wall displacement, which greatly influence the hemodynamic characteristics are analyzed. Results show that the proximal false lumen near the entry tear appears to be a vortex zone with a relatively lower volume fraction of RBCs, a low time-averaged wall shear stress (TAWSS) and a high oscillatory shear index (OSI), providing a suitable physical environment for the formation of atherosclerosis. The highest TAWSS is located in the narrow area of the distal true lumen which might cause further dilation. TAWSS distributions in the FSI model and the rigid wall model show similar trend, while there is a significant difference for the OSI distributions. We suggest that an integrated model is essential to simulate blood flow in a more realistic physiological environment with the ultimate aim of guiding clinical treatment.

A Comprehensive Study and Optimization of Magnetic Nanoparticle Drug Delivery to Cancerous Tissues via External Magnetic Field

Abstract Magnetic drug delivery to cancerous tissue as a noninvasive method is a promising cancer therapy. Several complex phenomena and parameters are involved in guiding nanoparticles to the targeted tissue and guaranteeing a predetermined distribution. A comprehensive Euler–Lagrangian method is utilized to simulate a realistic process of nanoparticle delivery and deposition in a cancerous tissue. Non-Newtonian and conductive blood flow in a typical vessel through a cancerous tissue in the presence of an external magnetic field is numerically modeled (both Lorentz and magnetization forces are considered). The cancerous tissue is assumed to be a multizone region with necrotic and live cell blocks. The effect of blood delivery to tissue cells via capillary vessels and blood drainage by the lymphatic system is taken into account. Particle paths and deposition are obtained using the contribution of all forces involved. The effects of Reynolds number (Re), magnetic number, addition of second magnetic source, and distribution of particles are also investigated. For all investigated conditions, the optimum magnetic number to maximize deposition is obtained.

A 3-D numerical simulation of non-Newtonian blood flow through femoral artery bifurcation with a moderate arteriosclerosis: investigating Newtonian/non-Newtonian flow and its effects on elastic vessel walls

In this study, a fluid-structure interaction (FSI) simulation of the blood flow in the femoral artery with a small occlusion is presented. For a more accurate simulation of the real conditions, computerized tomography (CT) scan was used to obtain a 3-D model of leg blood vessels, while the vessel was modeled as an isotropic elastic wall. By assuming a heartbeat period of 0.5 s, the inlet condition was considered as a time-dependent pulse using a non-Newtonian flow model. Blood flow was assumed nonlinear and incompressible, and Carreau model was used for blood rheological model. By considering unstable blood flow at the inlet, the involved hemodynamic parameters are velocity profile, vortices shapes, pressure drop, and streamlines. Furthermore, to determine the relationship between flow geometry and the vascular wall, wall shear stress (WSS) was calculated. By taking the real geometry of the vessel and fluidity of blood into account, comparison of computational results indicated a significant difference in velocity distribution and shear stress depending on whether the fluid-structure interaction is considered Newtonian or non-Newtonian. The results showed that employing Newtonian models for the blood flow does not lead to promising results at occluded areas and beyond them.

In silico study of patient-specific magnetic drug targeting for a coronary LAD atherosclerotic plaque

Coronary artery disease is the first cause of death across the world. Targeted delivery of therapeutics through controlled release of micro- and nano-particles remains a very capable approach to develop new strategies in treating restenosis and atherosclerotic plaques. In this research, to produce the arterial geometry, an image-processing was done using CT-scan images of a LAD coronary artery. After implementing the finite element mesh, the Fluid-Structure Interaction (FSI) simulation based on physiological boundary conditions was performed. Next, a Lagrangian description of particles dynamics in a non-Newtonian blood flow considering momentum equation of motion for each particle and the imposed external magnetic field was provided. Under the influence of the magnetic field, the optimal particle size scope for which the surface density of particles (SDP) adhered on the plaque lumen reaches its maximum was specified. Also, our results signify that applying a magnetic field can adversely affect the delivery of particles to the targeted site for near micron-size particles. Along with the evaluation of the Brownian and the gravitational forces on nanoparticles, the uniformity of the distribution of particles in the left coronary network with and without the presence of the magnetic field has been studied. In conclusion, the external magnetic field has increased the SDP adhered on the targeted surface by 49.4% and 59.7% for 400 and 600 nm particles, respectively.

Numerical study of entropy generation analysis for non-Newtonian MHD flow of blood in a porous channel with partial slip

In the present work, a numerical investigation of magnetohydrodynamic flow of blood through an arterial segment is carried out. A mathematical model of the problem is presented by considering blood...

Viscoelastic blood flow through stenosed artery in the presence of magnetic field

An unsteady analysis of non-Newtonian blood flow under stenotic condition in the presence of a transverse magnetic field has been carried out. The flowing blood is characterised by generalised Oldroyd-B having shear-thinning rheology. The arterial wall is considered to be rigid having cosine shaped stenosis in its lumen. The governing equations of motion accompanied by appropriate choice of the initial and boundary conditions are solved numerically by marker and cell (MAC) method and the results are checked for numerical stability with desired degree of accuracy. The quantitative analysis has been carried out finally which includes the respective profiles of the flow-field. The key factors like the wall shear stress and flow separation are also examined for further qualitative insight into the flow through arterial stenosis. The present results show quite consistency with several existing results in the literature which substantiate sufficiently to validate the applicability of the model under consideration.

Viscoelastic blood flow through stenosed artery in the presence of magnetic field

An unsteady analysis of non-Newtonian blood flow under stenotic condition in the presence of a transverse magnetic field has been carried out. The flowing blood is characterised by generalised Oldroyd-B having shear-thinning rheology. The arterial wall is considered to be rigid having cosine shaped stenosis in its lumen. The governing equations of motion accompanied by appropriate choice of the initial and boundary conditions are solved numerically by marker and cell (MAC) method and the results are checked for numerical stability with desired degree of accuracy. The quantitative analysis has been carried out finally which includes the respective profiles of the flow-field. The key factors like the wall shear stress and flow separation are also examined for further qualitative insight into the flow through arterial stenosis. The present results show quite consistency with several existing results in the literature which substantiate sufficiently to validate the applicability of the model under consideration.

Application of Caputo-Fabrizio Fractional Order Derivative (NFDt) in Simulating the MHD Flow of the Third Grade non-Newtonian Fluid in the Porous Artery

In this paper, the third grade non-Newtonian MHD blood flow in the porous arteries subjected to the periodic pressure gradient was studied using the Caputo-Fabrizio (NFDt ) time fractional order derivative. The time fractional model was solved by taking the Laplace and the finite Hankel transforms. Results were compared with those reported in the previous studies and good agreement was found. The Mathematica software was used to simulate the velocity profile and the Bessel functions with zero order and first order of first kind. The correlations between the flow velocity and the third grade non-Newtonian fluid parameter, the magnetic field and the porosity were negative. Nevertheless, the flow velocity increased with respect to the Womersely number.

Numerical solution of the Pulsatile, non-Newtonian and turbulent blood flow in a patient specific elastic carotid artery

The risk factor increases at the carotid bifurcation as a result of the changes in the flow of blood and phenomena such as flow separation, the rotational flow, and the effects of the shear stress induced by the walls, increasing the risk of injury. In this regard, using Fluent 16.2, the present study numerically simulates the pulsatile flow of the blood in a patient specific elastic carotid artery with physiological pulses and non-Newtonian and turbulent models. The result of wall shear stress showed that the being of rigid or elastic walls is much more important than that of the Newtonian or non-Newtonian blood, which in turn is more important than laminar or turbulent flow. Moreover by investigating Oscillatory Shear Index (OSI), it was found that the region prone to disease becomes larger as a Newtonian blood is assumed and that the k-ω model shows a larger area prone to disease compared with the k-ε model. In addition, the pressure contours showed that both pressure drop and critical pressure are higher in the k-ε and turbulent flow models in comparison with the k-ω and laminar flow models, respectively. By comparing various non-Newtonian models with the Newtonian one, it was found that the critical pressure is higher in the Carreau model compared with the Newtonian model where, in turn, it is higher than that in the Power-law model.

Blood Flow in a Radially Non Symmetric Stenosed Artery Under Slip Effect Through Porous Medium

A mathematical model is developed to analyze the non-Newtonian flow of blood in an axially symmetric but radially non symmetric stenosed artery through porous medium in the presence of slip velocity. Blood is modeled as Casson fluid to characterize the non-Newtonian behaviour. Flow characteristics like axial velocity, flow rate and impedance are expressed analytically. These expressions show remarkable variations in flow of blood through constricted artery. The effects of porosity, slip velocity and stenosis shape on the various flow characteristics have been examined and shown graphically. These results are in good agreement with the experimental findings existing in the literature and can aid medical practitioner to treat cardiovascular diseases.

Accounting for residence-time in blood rheology models: do we really need non-Newtonian blood flow modelling in large arteries?

Patient-specific computational fluid dynamics (CFD) is a promising tool that provides highly resolved haemodynamics information. The choice of blood rheology is an assumption in CFD models that has been subject to extensive debate. Blood is known to exhibit shear-thinning behaviour, and non-Newtonian modelling has been recommended for aneurysmal flows. Current non-Newtonian models ignore rouleaux formation, which is the key player in blood's shear-thinning behaviour. Experimental data suggest that red blood cell aggregation and rouleaux formation require notable red blood cell residence-time (RT) in a low shear rate regime. This study proposes a novel hybrid Newtonian and non-Newtonian rheology model where the shear-thinning behaviour is activated in high RT regions based on experimental data. Image-based abdominal aortic and cerebral aneurysm models are considered and highly resolved CFD simulations are performed using a minimally dissipative solver. Lagrangian particle tracking is used to define a backward particle RT measure and detect stagnant regions with increased rouleaux formation likelihood. Our novel RT-based non-Newtonian model shows a significant reduction in shear-thinning effects and provides haemodynamic results qualitatively identical and quantitatively close to the Newtonian model. Our results have important implications in patient-specific CFD modelling and suggest that non-Newtonian models should be revisited in large artery flows.

A numerical study on hemodynamics in the left coronary bifurcation with normal and hypertension conditions.

In this study, a three-dimensional analysis of the non-Newtonian blood flow was carried out in the left coronary bifurcation. The Casson model and hyperelastic and rigid models were used as the constitutive equation for blood flow and vessel wall model, respectively. Physiological conditions were considered first normal and then compliant with hypertension disease with the aim of evaluating hemodynamic parameters and a better understanding of the onset and progression of atherosclerosis plaques in the coronary artery bifurcation. Two-way fluid-structure interaction method applying a fully implicit second-order backward Euler differencing scheme has been used which is performed in the commercial code ANSYS and ANSYS CFX (version 15.0). When artery deformations and blood pressure are associated, arbitrary Lagrangian-Eulerian formulation is employed to calculate the artery domain response using the temporal blood response. As a result of bifurcation, noticeable velocity reduction and backflow formation decrease shear stress and made it oscillatory at the starting point of the LCx branch which caused the shear stress to be less than 1 and 2Pa in the LCx and the LAD branches, respectively. Oscillatory shear index (OSI) as a hemodynamic parameter represents the increase in residence time and oscillatory wall shear stress. Because of using the ideal 3D geometry and realistic physiological conditions, the values obtained for shear stress are more accurate than the previous studies. Comparing the results of this study with previous clinical investigations shows that the regions with low wall shear stress less than 1.20Pa and with high OSI value more than 0.3 are in more potential risk to the atherosclerosis plaque development, especially in the posterior after the bifurcation.

Permeability and fluid flow-induced wall shear stress of bone tissue scaffolds: Computational fluid dynamic analysis using Newtonian and non-Newtonian blood flow models

Among the factors that are important in successful bone tissue regeneration through scaffolds are permeability and fluid flow-induced wall shear stress (WSS) because of the direct contribution of these factors to cell bioactivities. The permeability of scaffolds is usually measured using fluids such as water, which are characterized as Newtonian materials with constant viscosity. However, using the fluid properties of blood as bases in measuring permeability can lead to more realistic results given that scaffolds are implanted in the body, where the only flowing fluid (i.e., blood) is a non-Newtonian fluid. Moreover, the linear relationship of WSS with fluid viscosity challenges the use of Newtonian fluids in determining WSS magnitude. With consideration for these issues, we investigated permeability and WSS through computational fluid dynamics (CFD) analyses of lattice-based and gyroid scaffold architectures with Newtonian and non-Newtonian blood flow properties. With reference to geometrical parameters and the pressure drops derived from the CFD analyses, the permeability levels of the Newtonian and non-Newtonian models were calculated by exploiting the classic and modified Darcy's equations, respectively. Results showed that both scaffold architectures were several times more permeable in the Newtonian blood flow models than in their non-Newtonian counterparts. Within the scaffolds, the non-Newtonian flow of blood caused almost twice the magnitude of WSS originating from Newtonian blood flow. These striking discrepancies in permeability and WSS between the two blood models were due to differences in their viscosity behaviors.

Modeling of unsteady non-Newtonian blood flow through a stenosed artery: with nanoparticles

Literature survey related to the nanoparticles reveals that nanofluids are getting popularity in hematological treatment. Development in this direction motivated us to write a theoretical study on unsteady blood motion in stenosed vessel with nanoparticles. Geometry of a stenosed arterial section is being written mathematically by an appropriate geometric expression. The constitutive equation of Carreau fluid model is used to characterize the dynamical behavior of the blood. The rheology of the blood is formulated mathematically by coupled partial differential equations. Similarly, the effects of nanoparticles are incorporated mathematically into governing equations by using Buonjiornio’s formulation. Mild stenotic condition is employed to reduce the two-dimensional differential equations to simple form. Numerical technique is being used to obtain the numerical solution to the existing problem. The obtained simulation reveals that the magnitude of velocity shows an accelerating behavior for Brownian motion parameter and shows deceleration trend on increasing the thermophoresis parameter. Similarly, the instantaneous behavior of blood flow pattern is shown through streamlines.

Hepatic Hemangiomas Alter Morphometry and Impair Hemodynamics of the Abdominal Aorta and Primary Branches From Computer Simulations.

Background: The formation of hepatic hemangiomas (HH) is associated with VEGF and IL-7 that alter conduit arteries and small arterioles. To our knowledge, there are no studies to investigate the effects of HH on the hemodynamics in conduit arteries. The aim of the study is to perform morphometric and hemodynamic analysis in abdominal conduit arteries and bifurcations of HH patients and controls.Methods: Based on morphometry reconstructed from CT images, geometrical models were meshed with prismatic elements for the near wall region and tetrahedral and hexahedral elements for the core region. Simulations were performed for computation of the non-Newtonian blood flow using the Carreau-Yasuda model, based on which multiple hemodynamic parameters were determined.Results: There was an increase of the lumen size, diameter ratio, and curvature in the abdominal arterial tree of HH patients as compared with controls. This significantly increased the surface area ratio of low time-averaged wall shear stress (i.e., SAR-TAWSS 100%) (24.1 ± 7.9 vs. 5 ± 6%, 11.6 ± 12.8 vs. < 0.1%, and 44.5 ± 9.2 vs. 21 ± 24% at hepatic bifurcations, common hepatic arteries, and abdominal aortas, respectively, between HH and control patients).Conclusions: Morphometric changes caused by HH significantly deteriorated the hemodynamic environment in abdominal conduit arteries and bifurcations, which could be an important risk factor for the incidence and progression of vascular diseases.

Mathematical modeling of power law and Herschel - Buckley non-Newtonian fluid of blood flow through a stenosed artery with permeable wall: Effects of slip velocity

A mathematical model of non-Newtonian blood flow through a stenosed artery is considered. The steadynon-Newtonian model is chosen characterized by the generalized power-law model and Herschel-Bulkley model incorporating the effect of slip velocity due to steanosed artery with permeable wall. The effects of slip velocity for non-Newtonian nature of blood on velocity, flow rate and wall shear stress of the stenosed artery with permeable wall are solved analytically. The effects of various parameters such as slip parameter (λ), power index (m) and different thickness of the stenosis (δ) on velocity, volumetric flow rate and wall shear stress are discussed through graphs.

Investigation of pumping mechanism for non-Newtonian blood flow with AC electrothermal forces in a microchannel by hybrid boundary element method and immersed boundary-lattice Boltzmann method.

Efficient pumping of blood flow in a microfluidic device is essential for rapid detection of bacterial bloodstream infections (BSI) using alternating current (AC) electrokinetics. Compared with AC electro-osmosis (ACEO) phenomenon, the advantage of AC electrothermal (ACET) mechanism is its capability of pumping biofluids with high electrical conductivities at a relatively high AC voltage frequency. In the current work, the microfluidic pumping of non-Newtonian blood flow using ACET forces is investigated in detail by modeling its multi-physics process with hybrid boundary element method (BEM) and immersed boundary-lattice Boltzmann method (IB-LBM). The Carreau-Yasuda model is used to simulate the realistic rheological behavior of blood flow. The ACET pumping efficiency of blood flow is studied in terms of different AC voltage magnitudes and frequencies, thermal boundary conditions of electrodes, electrode configurations, channel height, and the channel length per electrode pair. Besides, the effect of rheological behavior on the blood flow velocity is theoretically analyzed by comparing with the Newtonian fluid flow using scaling law analysis under the same physical conditions. The results indicate that the rheological behavior of blood flow and its frequency-dependent dielectric property make the pumping phenomenon of blood flow different from that of the common Newtonian aqueous solutions. It is also demonstrated that using a thermally insulated electrode could enhance the pumping efficiency dramatically. Besides, the results conclude that increasing the AC voltage magnitude is a more economical pumping approach than adding the number of electrodes with the same energy consumption when the Joule heating effect is acceptable.