Simple and rapid microfluidic device for processing raw human semen and separation of motile sperm based on their intrinsic behavior and morphology.

Sperm separation is pivotal in Assisted Reproductive Technology to address male infertility issues such as low sperm concentration or impaired motility. Traditional microfluidic devices, despite their fair success, often fall short due to complex fabrication and use, or lack of direct sample extraction methods. Our research introduces a microfluidic device designed to enhance sperm quality, focusing on improved motility and morphology, while remaining simple to fabricate and use in infertility clinics. The device features four chambers interconnected by channels, engineered to establish low shear rate limits, facilitating high-quality sperm separation. Utilizing the principle of rheotaxis, where superior sperm swim against the flow, our system concentrates top-quality sperm in designated chambers. A key feature of the device is its ability to use raw semen, eliminating the need for pre-washing. Clinical trials with both washed human sperm samples and raw semen demonstrate the device's efficacy, achieving up to 100% sperm isolation and morphological improvements in under 5 min. This approach overcomes the throughput constraints of traditional microfluidic methods, leveraging rheotaxis, near-boundary swimming, and parallelization to increase selected sperm concentration. This advancement has the potential to substantially improve the effectiveness of fertility treatments, offering new hope to individuals facing conception challenges.