Label-Free Particle Separation in a Viscoelastic Fluid by Using a Microfluidic Device

Abstract

A size-based microparticle separation has become indispensable in the fields of industrial production, chemical or biomedical research. Here we successfully carried out a size-based particle separation that arises from the synergistic combination between the elasto-inertial particle focusing and negative magnetophoresis. We obtained trajectories of the particle at the expanding area (250 μm ×50 μm) by (1) calculating magnetophoretic repulsion force and drag force through the analytical modeling, (2) deriving equations of motion to solve the velocity of the particles under the laminar flow. Numerical analysis under the magnetic field was employed in order to explain a mechanism of the particle in the case of the Newtonian and viscoelastic fluid, respectively. In conclusion, we demonstrated a size-based particle separation in a microchannel with the difference between the magnetophoretic repulsion force and the drag force influenced by size. We anticipate that our platform and analysis can provide a new pathway of particle separation by using a microfluidic system.