Comparison of Varied Microfluidic Ratchet Designs on Sperm Sorting and Quality in Low-Quality Samples

Infertility affects approximately ۱۷% of adults worldwide, with male factors contributing to ۲۰–۴۰% of cases. Conventional sperm selection methods, such as density gradient centrifugation and swim-up, can cause DNA damage via reactive oxygen species and mechanical stress, limiting their use in assisted reproductive technologies (ART), including intracytoplasmic sperm injection. Microfluidic systems provide a gentler alternative by exploiting sperm motility and morphology. Using polymethyl methacrylate sheets laser-engraved to create asymmetric ratchet geometries, four designs were evaluated at flow rates of ۰.۰۳۴ mL/min and ۰.۰۱۷ mL/min. Semen samples from patients with low sperm quality were injected, and output fractions were assessed for concentration, motility, morphology, and the sperm retrieval index (SRI), a composite metric normalized to World Health Organization standards. The results showed consistent improvements, with optimal designs yielding up to a fourfold increase in sperm concentration (e.g., from ۱۰ to ۴۰ million/mL) and over ۲۰-fold SRI enhancement, particularly at the lower flow rate, which minimized shear stress and promoted rheotactic trapping of motile sperm. These findings suggest that ratchet microchannels offer a simple and effective approach for sperm enrichment and improving ART outcomes without the need for centrifugation.

کلیدواژه ها:

Assisted Reproductive Techniques ، Microchannel ، Ratchet microchannel ، Sperm separation