D. Barthès-Biesel

University of Technology of Compiègne | UTC · BioMécanique et BioIngénierie (BMBI) - UMR 7338

We present a microfluidic method to measure the elastic properties of a population of microcapsules (liquid drops enclosed by a thin hyperelastic membrane). The method is based on the observation of flowing capsules in a cylindrical capillary tube and an automatic inverse analysis of the deformed profiles. The latter requires results from a full nu...

We address the question of the modelling of the fluid–structure interactions for a microcapsule enclosed by a finite-thickness wall, and of the prediction of the buckling behaviour when it is subjected to large displacements and deformations. Specifically, we model the strong coupling between the solid (the wall dynamics) and fluid (the flow inside...

We study the three-dimensional hydrodynamic interaction of a pair of identical, initially spherical capsules freely suspended in a simple shear flow under Stokes flow conditions. The capsules are filled with a Newtonian liquid (same density and viscosity as the suspending fluid). Their membranes satisfy the neo-Hookean constitutive law. We consider...

We computationally study the motion of an initially spherical capsule flowing through a straight channel with an orthogonal lateral branch, using a three-dimensional immersed-boundary lattice-Boltzmann method. The capsule is enclosed by a strain-hardening membrane and contains an internal fluid of the same viscosity as the fluid in which it is susp...

The Glubran 2 cyanoacrylate glue is a liquid embolic agent used to block blood vessels endovascularly. Typically mixed with an iodized oil (Lipiodol) for visualization under X-ray, it polymerizes when in contact with blood and tissues owing to the presence of ions and proteins. The objective of the study is to determine the influence of plasma prot...

Vascular embolization is a minimally invasive treatment used for the management of vascular malformations and tumors. It is carried out under X-ray by navigating a microcatheter into the targeted blood vessel, through which embolic agents are delivered to occlude the vessels. Cyanoacrylate liquid glues have been widely used for vascular embolizatio...

We computationally study the transient motion of an initially spherical capsule flowing through a right-angled tube bifurcation, composed of tubes having the same diameter. The capsule motion and deformation is simulated using a three-dimensional immersed-boundary lattice Boltzmann method. The capsule is modelled as a liquid droplet enclosed by a h...

A microfluidic technique is used to characterize the mechanical behavior of capsules that are produced in a two-step process: first, an emulsification step to form droplets, followed by a cross-linking step to encapsulate the droplets within a thin membrane composed of cross-linked proteins. The objective is to study the influence of the capsule si...

The objective of the paper is to determine the stable mechanical equilibrium states of an oblate capsule subjected to a simple shear flow, by positioning its revolution axis initially off the shear plane. We consider an oblate capsule with a strain-hardening membrane and investigate the influence of the initial orientation, capsule aspect ratio $a...

This article reviews the mechanical behavior of a capsule under the influence of viscous deforming forces due to a flowing fluid. It focuses on artificial capsules and vesicles with an internal liquid core enclosed by a very thin membrane with different constitutive laws. The recent modeling strategies are outlined together with their respective ad...

An inverse analysis of the flow of capsules in a square section microfluidic channel has been proposed to evaluate the elastic mod- ulus of the membrane of microcapsules. It is based on the comparison of the capsule deformed profiles measured experimentally with the ones computed numerically in the same flow situation. Experimentally, the microchan...

We consider an initially spherical capsule freely suspended in a planar hyperbolic flow and study the influence of the wall bending resistance on the capsule dynamics. The capsule wall is assumed to be made of a three-dimensional homogeneous elastic material. The fluid-structure interaction between the capsule and the external flow is modeled numer...

The objective of the paper is to study the effect of wall bending resistance on the motion of an initially spherical capsule freely suspended in shear flow. We consider a capsule with a given thickness made of a three-dimensional homogeneous elastic material. A numerical method is used to model the fluid-structure interactions coupling a boundary i...

In order to characterize the mechanical properties of bioartificial microcapsules, we have designed an inverse analysis technique that combines microfluidic experiments with a multi-physical numerical model. The experiments consist of flowing a suspension of capsules in a channel with cross section similar to the particle size. The mechanical prope...

We have designed a microfluidic system that enables both the fabrication of calibrated capsules and the in situ characterization of their mechanical properties. The fabrication setup consists of a double flow-focusing system. A human serum albumin aqueous solution is introduced in the central channel of a first Y-junction. Intercepted by the latera...

A microfluidic method is presented to measure the elastic membrane properties of a population of microcapsules with diameter of order 60 μm. The technique consists of flowing a suspension of capsules enclosed by a polymerized ovalbumin membrane through a square-section microfluidic channel with cross dimension comparable with the capsule mean diame...

Nous passons en revue les progrès expérimentaux, théoriques et numériques réalisés dans lʼétude de la dynamique des globules rouges et des systèmes biomimétiques, les vésicules et capsules sous écoulement. Nous mettons lʼaccent sur les approches continues de la modélisation de la déformabilité des cellules ainsi que sur la rhéologie du sang.

The objective of this study is to investigate the motion of an ellipsoidal capsule in a simple shear flow when its revolution axis is initially placed off the shear plane. We consider prolate capsules with an aspect ratio of two or three enclosed by a membrane, which is either strain-hardening or strain-softening. We seek the equilibrium motion of...

When a red blood cell (RBC) is subjected to an external flow, it is deformed by the hydrodynamic forces acting on its membrane. The resulting elastic tensions in the membrane play a key role in mechanotransduction and govern its rupture in the case of hemolysis. In this study, we analyze the motion and deformation of an RBC in a simple shear flow a...

The motion and deformation of a spherical elastic capsule freely flowing in a pore of comparable dimension is studied. The thin capsule membrane has a neo-Hookean shear softening constitutive law. The three-dimensional fluid–structure interactions are modelled by coupling a boundary integral method (for the internal and external fluid motion) with...

The large deformations of an initially-ellipsoidal capsule in a simple shear flow are studied by coupling a boundary integral method for the internal and external flows and a finite-element method for the capsule wall motion. Oblate and prolate spheroids are considered (initial aspect ratios: 0.5 and 2) in the case where the internal and external f...

The motion and deformation of a spherical elastic capsule freely suspended in a simple shear flow is studied numerically, focusing on the effect of the internal-to-external viscosity ratio. The three-dimensional fluid–structure interactions are modelled coupling a boundary integral method (for the internal and external fluid motion) with a finite e...

A capsule is a liquid drop enclosed by a solid, deformable membrane. To analyze the deformation of a capsule accurately, both the fluid mechanics of the internal and external fluids and the solid mechanics of the membrane must be solved precisely. Recently, many researchers have used discrete spring network models to express the membrane mechanics...

The study deals with a microfluidic method to investigate the transient behavior of microcapsules in flow. The technique consists of investigating ovalbumin microcapsules passing through a convergent–divergent microchannel made of PolyDiMethylSiloxane. We work with three types of square microchannel with, respectively, cross section values of h × h...

An inverse method is used to characterize the membrane mechanical behavior of liquid filled microcapsules. Cross-linked ovalbumin microcapsules are flowed and deformed into a cylindrical microchannel of comparable size. The deformed shape is compared to predictions obtained numerically when modeling a capsule under the same flow conditions. The unk...

This review presents the mechanical behavior of a capsule under the influence of viscous deforming forces due to a flowing fluid. We focus on artificial capsules that are initially spherical with an internal liquid core and that are enclosed by a very thin hyperelastic membrane with different constitutive laws. The recent modeling strategies are ou...

We introduce a new numerical method to model the fluid–structure interaction between a microcapsule and an external flow. An explicit finite element method is used to model the large deformation of the capsule wall, which is treated as a bidimensional hyperelastic membrane. It is coupled with a boundary integral method to solve for the internal and...

The objective of this review is to present the salient features of capsule mechanical behaviour under the influence of viscous deforming forces due to a flowing fluid. We focus on artificial capsules that are initially spherical with an internal liquid core and that are enclosed by a very thin hyperelastic membrane. Different constitutive laws, com...

A capsule is a liquid droplet enclosed in a thin hyperelastic membrane. Microcapsules have various biomedical applications and can be studied as models for circulating cells, especially red blood cells. While many numerical studies have focussed on initially-spherical capsules, the aim of this work is to model the behavior of an ellipsoidal capsule...

This article investigates the formation of albumin droplets in fatty esters by means of a flow focussing geometry where the continuous oil phase is introduced in the two lateral branches of a Y junction. The effect of the geometry is investigated in order to clarify the scales controlling the droplet generation with this type of fluid couple. The t...

The paper deals with a method to characterize the membrane mechanical properties of microcapsules. The technique consists in flowing microcapsules into a microchannel of comparable dimensions, observing the deformation as a function of the flow rate, and deducing the membrane elastic modulus by means of an inverse method based on a numerical model...

Bioartificial capsules consisting of an internal liquid protected by a thin membrane have potential thera-peutic uses, such as drug delivery in the microcirculation and artificial blood design. Numerical models are necessary to predict their behaviour in microflow conditions encountered during fabrication and transport. This problem involves strong...

We use a boundary integral formulation to investigate the collision of two identical capsules in simple shear flow. Each capsule consists of a viscous liquid drop enclosed by an elastic membrane. The hydrodynamic interaction is characterized by an irreversible cross-flow displacement after the capsules have crossed each other, as also observed for...

A capsule consists of an internal medium (pure or complex liquid), enclosed by a deformable membrane that is usually semi-permeable. Capsules are frequently met in nature (living cells) or in industrial processes (pharmaceutical, cosmetic or food industry). The motion, deformation and burst of a capsule under stress depend on three types of indepen...

We present a numerical model of the axisymmetric flow of an initially spherical capsule in a co-axial cylindrical tube. The capsule consists of a liquid droplet enclosed by a thin hyper-elastic membrane that is assumed to obey different membrane constitutive equations such as Mooney–Rivlin, Skalak et al. (1973) or Evans & Skalak (1980) laws. It is...

La présence de plusieurs capsules en écoulement dans un pore cylindrique peut conduire à des interactions hydrodynamiques importantes qui altèrent la déformation de chaque capsule. On considère le cas de deux capsules s'écoulant dans un tube et on étudie l'influence de la distance les séparant sur leur niveau d'interaction.

We present a numerical model of the hydrodynamic interactions between two capsules freely suspended in a simple shear flow. The capsules are identical and each consists of a liquid droplet enclosed by a thin hyperelastic membrane, devoid of bending resistance and obeying a neo-Hookean constitutive law. The two capsules are slightly prestressed with...

s of the 5th World Congress of Biomechanics

s of the 5th World Congress of Biomechanics

In the past three decades, there has been great progress in the mathematical modeling and computational methods for fluid mechanics of suspensions of micron-scale particles. In medical or biological applications, the particles can be very deformable, self propelled or both. Research on mathematical and computational methods for the modelling of sus...

The mechanical properties of a capsule membrane are evaluated by means of a compression experiment between two parallel plates. Since large deformations of the membrane are involved, the choice of the wall material constitutive law is essential. In this paper, we explore different classical laws to describe the behavior of the membrane and evaluate...

Fluidized bed bioartificial liver has been proposed as a temporary support to bridge patients suffering from acute liver failure to transplantation. In such a bioreactor, alginate beads hosting hepatocytes are in continuous motion during at least six hours. After having shown in vitro the functionality of such a device, the present study aims at an...

We present a numerical model of the hydrodynamic interactions between two capsules freely suspended in a simple shear flow (SSF). The capsules are identical and consist of a liquid droplet enclosed by a thin hyper-elastic membrane. Such particles can be used in applications where encapsulation of living cells or of active agents in a protecting mem...

We investigate the effect of an initial isotropic prestress on the mechanics of a spherical capsule freely suspended in a simple shear flow. The capsule consists of a drop of liquid enclosed by a very thin hyperelastic membrane. A sufficient prestress may prevent the buckling instability that arises at low shear rates when the membrane bending resi...

We analyze the deformation and bursting process of nonspherical organosiloxane capsules in centrifugal fields. Measurements were performed in a commercial spinning-drop tensiometer at different values of tube rotation. A theoretical analysis of the mechanics of initially ellipsoidal elastic shells subjected to centrifugal forces is developed where...

The dynamic response of an initially spherical capsule subject to different externally imposed flows is examined. The neo-Hookean and Skalak et al. (Biophys. J., vol. 13 (1973), pp. 245–264) constitutive laws are used for the description of the membrane mechanics, assuming negligible bending resistance. The viscosity ratio between the interior and...

Compression experiments between two parallel plates are performed on a series of biocompatible HSA-alginate capsules with two different membrane thicknesses. The capsule geometry and size as well as the average membrane thickness are first measured. The compression set-up is fitted with a sensitive force transducer that allows measurement of the co...

This paper deals with numerical study of the flow of a bioartificial capsule in a long axisymmetric pore with a hyperbolic entrance. The capsule consists of an infinitely thin and hyperelastic membrane filled with a Newtonian liquid. The solution of the problem is based on an integral formulation of Stokes equations along with a boundary element me...

The role of membrane surface viscosity is investigated in the transient response of an axisymmetric capsule following a sudden start of external flow. Results obtained in a recent study for capsules with a hyperelastic membrane [Phys. Fluids 12, 948 (2000)] are extended to account for membrane viscosity. The common feature between hyperelastic and...

We present a numerical model of the motion and deformation of an initially spherical liquid filled capsule freely suspended in a simple shear flow. Both fluids are Newtonian with the same dynamic viscosity. The particle Reynolds number is small so that the Stokes equations apply. The membrane is infinitely thin and hyperelastic. Two constitutive ma...

The transient deformation of an axisymmetric capsule freely suspended in a pure straining flow is studied, for sudden or periodic variations of the intensity of the rate of strain. The particle Reynolds number is supposed to be very small and the problem is solved numerically by means of the boundary integral method. In the case of a sudden start o...

Fluid-structure interactions are often met in Biomechanics. Indeed, tissues and blood vessels (arteries, veins) deform easily in order to adapt to the imposed fluid stresses. In the ease of microcirculation, the capillary, vessels mau be considered as rigid. but then the cells (red and white blood cells) have to deform. This paper presents some of...

This paper studies the rheological properties of ultrathin aminomethacrylate membranes that are synthesized at the interface between oil and water. We have measured the kinetics of the cross-linking reactions, the zero shear modulus, and the nonlinear rheological properties of those two-dimensional networks. The measurements were performed at a pla...

A boundary integral method is used to model the flow of capsules into pores. An axisymmetric configuration is considered where the capsule and the pore axis coincide. The channel is a cylinder with hyperbolic entrance and exit regions. The capsule has a discoidal unstressed shape, is filled with a Newtonian liquid and is enclosed by a very thin mem...

Wound healing is promoted by dressings that maintain a moist environment. Specifically, hydrocolloid dressings allow excess fluid to escape without permitting wound desiccation. However, the fluid handling capacity of hydrocolloid dressings depends on many factors such as the physicochemical properties of the gel formulation, and the design of the...

The motion of capsules freely suspended into another liquid subjected to flow is studied. Experimental evidence regarding the deformation of artificial capsules or of red blood cells in shear flows is presented. Results of filtration experiments conducted on red cell suspensions are also discussed. The equations describing the mechanics of a single...

The leading end of an infinitely long gas bubble which displaces a viscous surfactant solution in a capillary tube is studied. The surfactant is present at elevated concentration and has sorption controlled mass transfer. The displaced fluid wets the wall, forming a continuous liquid film between the bubble and the capillary wall. Both the thicknes...

The boundary element method is used to model the creeping flow of deformable capsules through cylindrical pores. The entrance and steady state values for the additional pressure drop, as well as the deformed shape of the capsule, can thus be predicted. The respective roles of capsule size and of membrane deformability are investigated.

A model for the low-Reynolds-number flow of a capsule through a constriction is developed for either constant-flow-rate or constant-pressure-drop conditions. Such a model is necessary to infer quantitative information on the intrinsic properties of capsules from filtration experiments conducted on a dilute suspension of such particles. A spherical...