Human sperm velocity approaching the walls under ultraconfinement

V.I. MARCONI; A.J. BANCHIO; BETTERA MARCAT M.A.

Viña del Mar

Congreso; Physics of Active Matter. Statphys 2019 Satellite Meeting; 2019

Recent advances in nano-fabrication and microfluidics are leading to novel applications in bioscience and nanomedicine [1]. Conventional in vitro fertilization methods have a performance of barely 30-35% of success. For this reason today the demand for improved methods, techniques and micro-devices, is prominent. In order to design new microfluidics devices to control human sperm populations it is essential to count with a good model for the dynamics of spermatozoa under micro and ultra confinement conditions. Our aim is to develop a simple phenomenological model [2] of the ultra confined human sperms capable of producing accurate predic- tions. Here, we propose and study three models for the interaction sperm?wall, based on the observed alignment of the cells parallel to walls. The three models differ in the functional form of the introduced phenomenological reorientation, responsible for the sperm alignment, as a function of the angle between the swimming direction at arrival and the wall axis. We found that as they approach the walls there is a decrease in the translational velocity. After the alignment parallel to the wall they recover the velocity, but it is not a full recovery, as seen in previous observations. We characterize the dependence of the average translational velocity loss and the detention time with the value of the unique adjustable parameter of the models. From comparison with experiments we find a range of the reorientation parameter values that reproduce qualitatively well the human sperm dynamics near wall, using a simple linear model [3].