Behavior of Motile Sperm in Taylor-Couette Flow: Effect of Shear Stress on the Behavior of Motile Sperm

Yasutaka Hayamizu,Takeshi Gonda,Toru Hyakutake,Shinichiro Yanase,Shinichi Morita,Koji Matsuura,Shigeru Ohtsuka

doi:10.4236/ojfd.2013.32a002

Abstract

Infertility is often cited as one of the causes of a declining birthrate, which has become a serious social problem in recent years. Processes by which motile sperm can be safely and easily sorted are therefore important for infertility treatment. Therefore, as a new sorting method, microfluidic sperm sorter using the microfluidic system has been developed. To improve more separation efficiency of this device, it is necessary to know the behaviors of motile sperm in the microchannel where the sperm undergo shear flow. The previous study implied the necessity of the modeling of motile sperm in the shear flow. In the present study, therefore, we experimentally investigated the behavior of the motile sperm in the Taylor-Couette flow using PTV (Particle Tracking Velocimetry) method. The experimental results showed that the ascent of the shear stress led to the increase in the sperm velocity, and the direction of the sperm velocity was opposite to that of the flow.

Highlights

Infertility is often cited as one of the causes of a declining birthrate, which has become a serious social problem in recent years
To improve more separation efficiency of this device, it is necessary to know the behaviors of motile sperm in the microchannel where the sperm undergo shear flow
The previous study implied the necessity of the modeling of motile sperm in the shear flow

Summary

Introduction

Infertility is often cited as one of the causes of a declining birthrate, which has become a serious social problem in recent years. The swim up method or the Percoll method is employed for sperm sorting. These methods need much time and sort sperm in a non-physiological environment, so damage such as DNA fragmentation is a major problem [1], and it might result in the sorting of sperm that is unsuitable for fertilization [2]. To improve more separation efficiency of this device, it is necessary to know the behaviors of motile sperm in the microchannel where the sperm undergo shear flow. The previous study implied the necessity of the modeling of motile sperm in the shear flow. We experimentally investigated the behavior of the motile sperm in the Taylor-Couette flow using PTV (Particle Tracking Velocimetry) method.

Experimental Apparatus

Experimental Method

Physical Property

Sperm Velocity

Conclusions