Abstract
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 without affecting the sorting process because the chamber is blocked while sorting. At the end of sorting, the collateral chamber is open and then using just pipette to derive high quality sperms instead of pump. Controllable numbers, ranging from 2000 to 10000, of sperms can be collected with a motility (>70μm) ratio higher than 70%, suitable for in-vitro fertilization (IVF). Hot embossing lithography process is presented. Microchannels are replicated on a Polymethylmetacrylate (PMMA) stamp with thickness of 1 mm. With low cost and high replication precision, we can make it a clinical chip.