Elasto-inertial migration of deformable capsules in a microchannel

Abstract

In this paper, we study the dynamics of deformable cells in a channel flow of Newtonian and polymeric fluids and unravel the effects of deformability, elasticity, inertia, and size on the cell motion. We investigate the role of polymeric fluids on the cell migration behavior and the performance of inertial microfluidic devices. Our results show that the equilibrium position of the cell is on the channel diagonal, in contrast to that of rigid particles, which is on the center of the channel faces for the same range of Reynolds number. A constant-viscosity polymeric fluid, modeled using an Oldroyd-B constitutive equation, drives the cells toward the channel centerline, while a shear-thinning polymeric fluid, modeled using a Giesekus constitutive equation, pushes the cells toward the channel wall. The findings of this paper suggest that the addition of polymers in microfluidic devices can be used to enhance the throughput of cell focusing and separation devices at a low cost. This study provides an insight on the role of rheological properties of the fluid and the ways that they can be tuned to control the focal position of the cells.

Analogue tuning of particle focusing in elasto-inertial flow

“…However, due to the finite inertia considered in our simulations, the particle does not reach the corner, but settles at a certain distance from it, and the symmetrical first normal stress difference about the diagonal axis prevents the slow migration of the particle along the equilibrium manifold [31]. This result is similar to what observed in the case of deformable capsules in a Newtonian fluid [52]. The interested reader is referred to the work by Trofa et al [58] and Lashgari et al [31] for further analysis on the different migration dynamics of particles in square channels.…”

“…In order to gain more physical insight on our experimental observations, we performed three-dimensional direct numerical simulations of a rigid spherical particle in a polymeric flow modelled by the FENE-P model. This model allows to reach higher Wi in dilute polymer flows than other viscoelastic models such as the Oldroyd-B [52] and better prediction of shear viscosity at high shear rates than Giesekus fluids [53] and Phan-Tien Thanner models [54].…”

Computational inertial microfluidics: a review

“…Near the wall, the deformation rate is high, and after a quick deformation, the particle shape becomes approximately steady. In another study, Raffiee et al 73 investigated the equilibrium position of cells with a blockage ratio of 0.2 in a square channel using the front-tracking method. According to their results, unlike rigid particles that reach equilibrium position located on the center of the channel walls, the focusing position of the cell is on the channel diagonal at the same range of Re.…”

In vitro analysis of multiple blood flow determinants using red blood cell dynamics under oscillatory flow

“…Viscous stresses facilitate RBC deformation, whereas elastic stresses suppress it. Hence, an increase in medium viscosity or a decrease in medium elasticity enhances RBC deformation 41,42 and thus optical transmission. We prepared suspending media with different viscoelastic properties (Table 1) to confirm this.…”