Hydraulic extraction of high quality sperms from a dual gradient sperm sorter for in-vitro fertilizatio

This paper proposes a selection and extraction strategy to acquire high quality sperms from a biomimetic microfluidic device capable of generating a dual gradient flow field for motile sperm sorting. The sorter consists of a straight flow zone, a rapidly expansion sector for sperm sorting by gradient up-stream flow, and a dumbbell channel for dead sperms separation at the outlet. A collateral runner is set at the front area of the expansion sector, but mostly kept in dry state without affecting the sorting process. At the end of sorting, a pressure was applied from both the inlet and outlet to flush the high quality sperms into the collateral runner for collection. Controllable numbers, ranging from 1 to 15000, of sperms can be collected with a motility (>60µm) ratio higher than 60%, suitable for in-vitro fertilization (IVF).