Combined effects of fluid type and particle shape on particles flow in microfluidic platforms

Abstract

Recent numerical analyses to optimize the design of microfluidic devices for more effective entrapment or segregation of surrogate circulating tumor cells (CTCs) from healthy cells have been reported in the literature without concurrently accommodating the non-Newtonian nature of the body fluid and the non-uniform geometric shapes of the CTCs. Through a series of two-dimensional proof-of-concept simulations with increased levels of complexity (e.g., number of particles, inline obstacles), we investigated the validity of the assumptions of the Newtonian fluid behavior for pseudoplastic fluids and the circular particle shape for different-shaped particles (DSP) in the context of microfluidics-facilitated shape-based segregation of particles. Simulations with a single DSP revealed that even in the absence of internal geometric complexities of a microfluidics channel, the aforementioned assumptions led to 0.11-0.21W (W is the channel length) errors in lateral displacements of DSPs, up to 3-20% errors in their velocities, and 3-5% errors in their travel times. When these assumptions were applied in simulations involving multiple DSPs in inertial microfluidics with inline obstacles, errors in the lateral displacements of DSPs were as high as 0.78W and in their travel times up to 23%, which led to different (un)symmetric flow and segregation patterns of DSPs. Thus, the fluid type and particle shape should be included in numerical models and experiments to assess the performance of microfluidics for targeted cell (e.g., CTCs) harvesting.

Computational inertial microfluidics: a review

“…Since the LBM is a weakly compressible scheme, it is not very accurate for the pressure field, which may negatively affect the lift and drag forces acting on moving particles. Although recent LBM studies have shown considerable progress in enhanced computational performance, nonspherical particles (using DSP-LBM method), or non-Newtonian fluids, [137][138][139][140] more research is needed to investigate the accuracy and reliability of the LBM for inertial particle microfluidics.…”

A Review on Contact and Collision Methods for Multi-Body Hydrodynamic Problems in Complex Flows

“…The LBM formulation above has been commonly used to simulate flow of circular-cylindrical particles in Newtonian fluid flow. The extension of the model to simulate settling or flow trajectories of 2D angular-shaped (e.g., boomerang-, star-, rectangular-, hexagonal-shaped particles) and circular-shaped (e.g., elliptical) particles in Newtonian or non-Newtonian fluid flow were provided by Başağaoğlu et al [145,146]. In the coupled IBM-LBM, the IBM is typically used to calculate the FSI forces, and LBM is used to simulate the flow field by incorporating the FSI as the source term in the LB equation.…”

“…Their simulations revealed that any irregularity on wall surfaces could cause temporary or permanent clogging of the flow field if hydrodynamic forces on the particle cannot overcome unevenly distributed repulsive barrier on the channel wall. Başağaoğlu et al used the LJ 6-12 model to simulate chemotatic motility [220] or flow [221,222] of circular particles in a Newtonian fluid, settling or flow of a mixture of non-circular particles in a Newtonian fluid, and flow of a mixture of non-circular particles in a non-Newtonian fluid [145,146]. Using the LJ 6-12 potentials, Başağaoğlu et al [146] demonstrated that steady vortices do not necessarily always control particle entrapments nor do larger particles get selectively entrapped in steady vortices in a microfluidic chamber.…”

The influence of cell elastic modulus on inertial positions in Poiseuille microflows

“…It has also previously been shown, both computationally and experimentally, that the shape of rigid particles can influence their migration patterns in a microchannel (43)(44)(45)(46). It is quite likely that it will similarly affect deformable particles such as cells.…”