The Lift on a Tank-Treading Ellipsoidal Cell in a Shear Flow

Olla, Piero

doi:10.1051/jp2:1997201

Cited by 76 publications

(112 citation statements)

References 13 publications

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“…Interestingly, at very small excess area we obtain from (50) that N 1 ∼ ∆ 1 2 , and vesicle migration is independent of the viscosity contrast. The values of the prefactor (53) are of the same order of magnitude as reported in studies considering a tank-treading ellipsoid 39 or numerical simulations of a vesicle with no viscosity contrast 25 .…”

Section: Rheologysupporting

confidence: 54%

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Dynamics of a viscous vesicle in linear flows

2007

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An analytical theory is developed to describe the dynamics of a closed lipid bilayer membrane (vesicle) freely suspended in a general linear flow. Considering a nearly spherical shape, the solution to the creeping-flow equations is obtained as a regular perturbation expansion in the excess area. The analysis takes into account the membrane fluidity, incompressibility and resistance to bending. The constraint for a fixed total area leads to a non-linear shape evolution equation at leading order. As a result two regimes of vesicle behavior, tank-treading and tumbling, are predicted depending on the viscosity contrast between interior and exterior fluid. Below a critical viscosity contrast, which depends on the excess area, the vesicle deforms into a tank-treading ellipsoid, whose orientation angle with respect to the flow direction is independent of the membrane bending rigidity. In the tumbling regime, the vesicle exhibits periodic shape deformations with a frequency that increases with the viscosity contrast. Non-Newtonian rheology such as normal stresses is predicted for a dilute suspension of vesicles. The theory is in good agreement with published experimental data for vesicle behavior in simple shear flow.

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Section: Rheologysupporting

confidence: 54%

“…Hence, in the stationary state all excess area is stored in the f 2±2 modes. Substituting the stationary amplitudes (39) in the relation for the inclination angle (38) and expanding for small values of the excess area ∆ we obtain …”

Section: Results: Simple Shear Flowmentioning

confidence: 99%

Dynamics of a viscous vesicle in linear flows

2007

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“…124 It is notable that in case of a rigid ellipsoid, the particle does not maintain a fixed inclination but will start to tumble in an unsteady fashion. 125 Thus, deformability plays an essential role in ensuing the tank-treading motion.…”

Section: Deformability-selective Cell Separationmentioning

confidence: 99%

“…Here, C L denotes the dimensionless lift coefficient which has been formulated in various formats, for instance in terms of reduced volume , 116 as a function of viscosity ratio k and ellipsoid geometrical measures, 125 or in terms of excess area D and k. 119 Assuming flow with negligible inertia, the corresponding lift force can be calculated using Stokes law as F L ¼ 6plRv L . In these models, it is presumed that the lift force always acts in the opposite direction of the wall to push the particle towards the centerline.…”

Section: Deformability-selective Cell Separationmentioning

confidence: 99%

Hydrodynamic mechanisms of cell and particle trapping in microfluidics

2013

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Focusing and sorting cells and particles utilizing microfluidic phenomena have been flourishing areas of development in recent years. These processes are largely beneficial in biomedical applications and fundamental studies of cell biology as they provide cost-effective and point-of-care miniaturized diagnostic devices and rare cell enrichment techniques. Due to inherent problems of isolation methods based on the biomarkers and antigens, separation approaches exploiting physical characteristics of cells of interest, such as size, deformability, and electric and magnetic properties, have gained currency in many medical assays. Here, we present an overview of the cell/particle sorting techniques by harnessing intrinsic hydrodynamic effects in microchannels. Our emphasis is on the underlying fluid dynamical mechanisms causing cross stream migration of objects in shear and vortical flows. We also highlight the advantages and drawbacks of each method in terms of throughput, separation efficiency, and cell viability. Finally, we discuss the future research areas for extending the scope of hydrodynamic mechanisms and exploring new physical directions for microfluidic applications.

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“…This scaling as well as the dependence of the lift velocity upon vesicle aspect ratio are consistent with theoretical predictions by Olla [J. Phys. II France 7, 1533-1540(1997]. …”

mentioning

confidence: 99%

Hydrodynamic lift of vesicles under shear flow in microgravity

et al. 2008

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The dynamics of a vesicle suspension in a shear flow between parallel plates has been investigated under microgravity conditions, where vesicles are only submitted to hydrodynamic effects such as lift forces due to the presence of walls and drag forces. The temporal evolution of the spatial distribution of the vesicles has been recorded thanks to digital holographic microscopy, during parabolic flights and under normal gravity conditions. The collected data demonstrates that vesicles are pushed away from the walls with a lift velocity proportional toγR 3 /z 2 whereγ is the shear rate, R the vesicle radius and z its distance from the wall. This scaling as well as the dependence of the lift velocity upon vesicle aspect ratio are consistent with theoretical predictions by Olla [J. Phys. II France 7, 1533-1540(1997].

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The Lift on a Tank-Treading Ellipsoidal Cell in a Shear Flow

Cited by 76 publications

References 13 publications

Dynamics of a viscous vesicle in linear flows

Dynamics of a viscous vesicle in linear flows

Hydrodynamic mechanisms of cell and particle trapping in microfluidics

Hydrodynamic lift of vesicles under shear flow in microgravity

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