Repeated pulses of ultrasound maintain sperm motility†

Sperm motility is a primary criterion for selecting viable and functional sperm in assisted reproduction, where the most motile sperm are used to increase the likelihood of successful conception. Traditional chemical agents to enhance motility pose embryo-toxicity risks, necessitating safer alternatives. This study investigates the use of low-intensity pulsed ultrasound exposure as a non-invasive treatment within an acoustofluidic device to maintain sperm motility. We utilized a droplet-based platform to examine the effects of repeated ultrasound pulses on single human sperm cells. Our findings demonstrate that repeated pulsed ultrasound maintains sperm motility over an hour, with significant improvements in motility parameters by at least 25% as compared to non-exposed sperm. Moreover, we show that the motility enhancements by repeated pulsed ultrasound are more significant in initially non-progressive sperm. Importantly, this method did not compromise sperm viability or DNA integrity. These results suggest a viable, sperm safe approach to enhance and maintain sperm motility, potentially improving assisted reproduction outcomes.