Automated microparticle positioning using a pair of ultrasound-actuated microbubbles for microfluidic applications

We present an advanced single-particle positioning technique that uses ultrasound-driven microstreaming induced by two microbubbles to position microparticles across the width of a microchannel or to direct them to desired exits of a Y-shaped microchannel. An open-loop control algorithm has been devised to facilitate the automatic detection, tracking, and precise positioning of microparticles in the presence of two microbubbles. Our control system is capable of performing particle positioning in multiple steps, individually for each microparticle, with arbitrary starting positions without requiring prior particle focusing or flow conditioning. We have also evaluated the accuracy enhancement of particle positioning using two microbubbles, in comparison to the system's results using only one microbubble.

Automated summary

We propose an advanced single-particle positioning technique using two microbubbles-induced ultrasound-driven microstreaming to position microparticles in a microchannel or direct them to desired exits of a Y-shaped microchannel. An open-loop control algorithm is developed for automatic detection, tracking, and precise positioning of microparticles in the presence of two microbubbles. The accuracy enhancement of particle positioning using two microbubbles is evaluated compared to the system's results with one microbubble.