Title: Application of numerical simulation to improve efficiency of a sperm sorter

This paper describes a study in which a numerical simulation was used to improve the separation efficiency of a sperm sorter using a microfluidic system. First, by using 31 sperms, the sperm motion was modeled as a sinusoidal wave. The modeled sperm were supposed to move while vibrating in the fluid in the microchannel. In this analysis, the number of sperm extracted at an outlet channel and the rate of the rapid motile sperm were obtained for a wide range of flow velocities in the microchannel. By varying the channel height, sperm inlet channel width, and position, it was clarified that the separation efficiency is highly dependent on the fluid velocity in the channel. These results may be very valuable for improving the device configuration and aiming for further improvements in efficiency in the future.