Acoustofluidic-Based Motile Sperm Isolation Using Microvortices

The enritchment of motile sperm constitutes a pivotal stage in the realm of assisted reproductive technology. In this article, a technique for motile sperm sorting using on-chip manipulation via acoustofluidics is presented. The traveling bulk acoustic waves generated in the ultrasonic range will result in oscillation of air bubbles trapped in the horseshoe-shaped structures embedded within the microfluidic channel. Subsequently, the microvortices formed through acoustic streaming were used to trap sperms within the flow field. To our knowledge, this is the first report on the isolation of motile sperm by acoustic-induced vortices. We used COMSOL simulation to confirm the formation of the microvortices via bulk acoustic waves traveling across the channel. We finally demonstrated that by switching off the source of acoustic waves, the motile sperms can find a way to exit vortices to the output.