Turning the corner in fertility: high DNA integrity of boundary-following sperm

We present a passive microfluidic sperm selection strategy that collects motile sperm based on their preference to follow boundaries and turn corners. Clinical assessment of selected human sperm from the device revealed a strong correlation between high DNA integrity and the tendency for sperm to follow boundaries. Human sperm with preference to follow boundaries on the left- or right-hand sides have higher (>51%) DNA integrity than straight swimmers and significantly higher (>67%) DNA integrity than sperm in raw semen. Boundary following behaviour offers a strategy to selecting sperm with the highest DNA integrity to improve the success rate of assisted reproduction.