Particle Focusing in a Straight Microchannel with Non-Rectangular Cross-Section.

Uihwan Kim,Joo-Yong Kwon,Taehoon Kim,Younghak Cho

doi:10.3390/mi13020151

Uihwan Kim, Joo-Yong Kwon + Show 2 more

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https://doi.org/10.3390/mi13020151

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Abstract

Recently, studies on particle behavior under Newtonian and non-Newtonian fluids in microchannel have attracted considerable attention because particles and cells of interest can be manipulated and separated from biological samples without any external force. In this paper, two kinds of microchannels with non-rectangular cross-section were fabricated using basic MEMS processes (photolithography, reactive ion etching and anisotropy wet etching), plasma bonding and self-alignment between two PDMS structures. They were used to achieve the experiments for inertial and elasto-inertial particle focusing under Newtonian and non-Newtonian fluids. The particle behavior was compared and investigated for different flow rates and particle size in the microchannel with rhombic and equilateral hexagonal cross section. We also investigated the influence of Newtonian fluid and viscoelastic fluid on particle migration in both microchannels through the numerical simulation. The experimental results showed the multi-line particle focusing in Newtonian fluid over a wide range of flow rates, but the single-line particle focusing was formed in the centerline under non-Newtonian fluid. The tighter particle focusing appeared under non-Newtonian fluid in the microchannel with equilateral hexagonal cross-section than in the microchannel with rhombic cross section because of the effect of an obtuse angle. It revealed that particles suspended in the channel are likely to drift toward a channel center due to a negative net elasto-inertial force throughout the cross-sectional area. Simulation results support the present experimental observation that the viscoelastic fluid in the microchannel with rhombic and equilateral hexagonal cross-section significantly influences on the particle migration toward the channel center owing to coupled effect of inertia and elasticity.

Highlights

We investigated the particle focusing in Newtonian fluid and observed the migration of particles in non-Newtonian viscoelastic fluid
The shear rate as a differential of the fluid velocity is of particular importance in elasto-inertial particle focusing since it is highly associated with the competing mechanism of the inertial lift force between shear gradient and wall interaction [36]
Theunder experimental fluid and non-Newtonian fluids according to the flow rate and particle size

Summary

Introduction

1. Introduction with regard to jurisdictional claims in Recently, there have been numerous studies to separate particles and cells from complex and heterogeneous samples in medical, biological, and chemical fields in microfluidic channels as a passive particle manipulating technique. Introduction with regard to jurisdictional claims in Recently, there have been numerous studies to separate particles and cells from complex and heterogeneous samples in medical, biological, and chemical fields in microfluidic channels as a passive particle manipulating technique This technique does not require any external force, it allows a high performance over a wide range of flow rates, high resolution, and a better efficiency in processing time with reduced sample consumption in comparison with traditional separation methods such as flow cytometry [1,2,3,4,5].

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