Prediction of sperm motion behavior in microfluidic channel using sperm swimming model

Several investigations have recently been conducted using microfluidic channels to sort highly motile sperm and thereby increase the probability of fertilization. To further enhance the efficiency of sperm sorting, predicting sperm movement in microfluidic channels through simulation techniques could be beneficial. In this study, we constructed a sperm swimming model based on the concept of an agent-based model. This model allows analysis at the same spatio-temporal scale similar to microfluidic channels. Sperm movement was simplistically modeled as a random walk, utilizing the distribution of sperm velocity and deflection angle obtained from experimental data. We have developed a thigmotaxis model to describe the phenomenon where sperm near the wall exhibit a reduced tendency to move away from it. Additionally, we created a rheotaxis model, in which sperm reorient in the direction opposite to the flow depending on the shear rate. Using these models, we investigated sperm behaviors within a microchannel featuring a tapered area. The results reveal that sperm accumulate within the tapered area, leading to a significant increase in sperm concentration for specific flow velocity ranges in the microchannel. This model provides valuable information for predicting the effects of sperm sorting in various microfluidic channels.