Multi-dimensional-double-spiral (MDDS) inertial microfluidic platform for sperm isolation directly from the raw semen sample

Here, we propose a fully-automated platform using a spiral inertial microfluidic device for standardized semen preparation that can process patient-derived semen samples with diverse fluidic conditions without any pre-washing steps. We utilized the multi-dimensional double spiral (MDDS) device to effectively isolate sperm cells from other non-sperm seminal cells (e.g., leukocytes) in the semen sample. The recirculation platform was employed to minimize sample dependency and achieve highly purified and concentrated (up to tenfold) sperm cells in a rapid and fully-automated manner (similar to 10 min processing time for 50 mL of diluted semen sample). The clinical (raw) semen samples obtained from healthy donors were directly used without any pre-washing step to evaluate the developed separation platform, which showed excellent performance with similar to 80% of sperm cell recovery, and > 99.95% and > 98% removal of 10-mu m beads (a surrogate for leukocytes) from lowviscosity and high-viscosity semen samples, respectively. We expect that the novel platform will be an efficient and automated tool to achieve purified sperm cells directly from raw semen samples for assisted reproductive technologies (ARTs) as an alternative to density centrifugation or swim- up methods, which often suffer from the low recovery of sperm cells and labor-intensive steps.

Automated summary

In this study, a fully-automated platform using a spiral inertial microfluidic device for standardized semen preparation is proposed. The platform can process patient-derived semen samples with diverse fluidic conditions without any pre-washing steps. The developed separation platform showed excellent performance in isolating sperm cells from non-sperm seminal cells and achieving highly purified and concentrated sperm cells in a rapid and fully-automated manner.