Viscous Cervical Environment-on-a-Chip for Selecting High-Quality Sperm from Human Semen

Area of Science:

• Biophysics
• Reproductive Biology
• Biomaterials

Background:

• Cervical mucus acts as a natural filter, selecting sperm with optimal motility and morphology for fertilization.
• Understanding sperm selection mechanisms in the female reproductive tract is crucial for addressing male infertility.

Purpose of the Study:

• To develop a microfluidic device that mimics the human cervical canal's biophysical environment for sperm sorting.
• To investigate the in vivo sperm selection principle using a biomimetic approach.
• To evaluate the effectiveness of the device in selecting high-quality sperm.

Main Methods:

• A microfluidic sperm-sorting chip was designed using a viscous medium (polyvinylpyrrolidone: PVP) to simulate cervical mucus.
• The viscosity of the PVP solution was precisely tuned to match that of cervical mucus.
• Sperm selection was experimentally evaluated in vitro and theoretically analyzed using a convection-diffusion mechanism.

Main Results:

• The microfluidic chip successfully imitated the biophysical properties of cervical mucus.
• Convection flow was identified as dominant in the low-viscosity medium, facilitating sperm and debris transport with reduced dispersion.
• Sperm selected by the chip exhibited significantly higher motility, normal morphology, and DNA integrity.

Conclusions:

• The biomimetic sperm-sorting chip offers a promising tool for improving male fertility by selecting high-quality sperm.
• This technology can advance our understanding of sperm transport mechanisms in the female reproductive tract.
• The chip provides a novel platform for fertility research and clinical applications.