Continuous focusing of microparticles using inertial lift force and vorticity via multi-orifice microfluidic channels

We developed a new microfluidic method for focusing microparticles through the combined use of inertial lift forces and turbulent secondary flows generated in a topographically patterned microchannel. The mechanism of particle focusing is based on the hydrodynamic inertial forces exerted on particles migrating along a non-circular microchannel, i.e.tubular pinch effect and wall effect, which induce particle movement away from walls and along a specific lateral position in the microchannel. With the extraordinary geometry of multi-orifice microchannel, an ordered and focused particle distribution was achieved at central or side regions according to a particle Reynolds number (Re_p) range. The focusing of particles was controlled by the particle Reynolds number, microchannel length, and volume fraction of particles in suspension. This method will be beneficial in particle focusing processes in a microfluidic device since it offers continuous, high-throughput performance and simple operation.