Inertial Focusing Chip Based on Superposed Secondary Flows

Inertial focusing has been widely used in particle/cell separation and flow cytometry. In this work we presented an improved inertial focusing chip, consisting of an annular channel with obstacles distributed on the inner wall. Two types of secondary flows were generated and then superposed, thus enhanced the impact on particles. The simulation and experimental results showed that the enhanced secondary flow allowed precise focusing of particles and improved the focusing efficiency. The developed chip achieved a focusing width of ≈11.3 µm for 10.7 µm particles with a flow rate of ≈300 µL/min. This inertial focusing chip could be used for high-sensitive optical detection, especially for flow cytometry,