Simulation, Assessment, and Improvement of a MicrofluidicChip Used for Motile-Sperms Separation

Nowadays, infertility is one of the significant concerns of the World Health Organization (WHO), contributing to a large portion of its annual expenditure. Recent studies reveal that approximately 15% of couples worldwide (more than 50 million couples) encounter infertility problems that are caused by defects in the male or female fertility factors. Although medical advancements have successfully helped a lot of couples with their infertility by assisted reproductive technologies (ART), sperm selection, a crucial stage in ART, has remained challenging. Microfluidic devices are systems that control the movement of minute amounts of fluid using channels in micrometer dimensions, which have a wide range of applications, especially in medicine. This technology can help to enhancethe quality of sorted sperm and be applied to boost our knowledge of sperm behavior and effects of different sperm selection mechanisms within the ART. Here, the efficiency of a microfluidic device having an application in the separation of motile sperm was studied using computational fluid dynamics method and its two-phase-flow module. Laminar flow and Level-set modules were used in this simulation. The mentioned device has three input and three output channels, two channels for sample media and one for buffer. Furthermore, it has a main separation channel, which width becomes wider gradually from the beginning to the end. Thus, output channels have wider width. After simulation, the results were validated using the results of previous experimental and simulation works in this matter. Afterward, to increase the device’s efficiency, the width of the output channel used for the buffer is being altered which prevents the wasting of the motile sperm in buffer. Simulation has shown that increasing the buffer output’s width by 4 times of input fluids channel’s width would cause decreasing the volume fraction of buffer in sample’s outlet to 1%. Therefore, this geometry is presented as the appropriate geometry for separation of motile sperm. In further studies, it is suggested that the last device be manufactured and studied to be validated its efficiency by experiment.