A microfluidic “treadmill” for sperm selective trapping according to motility classification

Sperm motility analysis is an indispensable test in male infertility diagnosis. The current microscopic method cannot select the sperm of specific velocity for further in vitro Fertilization (IVF) usage or research purposes. Here, we report a novel and simple microfluidic device capable of balancing sperm´s swimming speed with local flow velocity. The results suggested that sperm motility was quantitatively graded and sperm with different average straight line velocity (VSL) 40.5 ± 3.0, 27.2 ± 0.6 and 18.7 ± 0.6 μm/s respectively were automatically trapped in corresponding regions. Sperm motility classification (SMC) and sperm trapping may facilitate both the diagnosis of male infertility and further studies on sperm physiological behavior.