Continuous size-based separation of microparticles in a microchannel with symmetric sharp corner structures

Abstract

A new microchannel with a series of symmetric sharp corner structures is reported for passive size-dependent particle separation. Micro particles of different sizes can be completely separated based on the combination of the inertial lift force and the centrifugal force induced by the sharp corner structures in the microchannel. At appropriate flow rate and Reynolds number, the centrifugal force effect on large particles, induced by the sharp corner structures, is stronger than that on small particles; hence after passing a series of symmetric sharp corner structures, large particles are focused to the center of the microchannel, while small particles are focused at two particle streams near the two side walls of the microchannel. Particles of different sizes can then be completely separated. Particle separation with this device was demonstrated using 7.32 μm and 15.5 μm micro particles. Experiments show that in comparison with the prior multi-orifice flow fractionation microchannel and multistage-multiorifice flow fractionation microchannel, this device can completely separate two-size particles with narrower particle stream band and larger separation distance between particle streams. In addition, it requires no sheath flow and complex multi-stage separation structures, avoiding the dilution of analyte sample and complex operations. The device has potentials to be used for continuous, complete particle separation in a variety of lab-on-a-chip and biomedical applications.

On the 3D distribution and size fractionation of microparticles in a serpentine microchannel

“…A geometrical key parameter for particle focusing is a cross-sectional change in streamwise direction (orifices), inducing strongly curved streamlines and thus centrifugal forces on suspended particles. Therefore, MOFF channels have been shown to achieve size fractionation performances of up to 100% (Park and Jung 2009;Sim et al 2011;Fan et al 2014). Studies, e.g.…”

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