ABSTRACT
Objective Sperm screening is an essential step in IVF procedures. The swim-up method, an assay on sperm motility, is used clinically to select the ideal sperm for subsequent manipulation. However, additional parameters, including acrosome reaction capability, chemotaxis, and thermotaxis are also important indicators of mammalian sperm health. To monitor both sperm motility and chemotaxis simultaneously during sperm screening, we designed and constructed a microdevice comprising a straight channel connected with a bi-branch channel that mimics the mammalian female reproductive tract. Methods The width and length of the straight channel were optimized to select the motile sperm. Cumulus cells were selectively cultured in the bi-branch channel to generate a chemoattractant-forming chemical gradient. Sperm chemotaxis was represented by the ratio of the sperm swimming towards different branches. Results The percentage of motile sperm was improved from ( 58. 5 ± 3. 8 ) % to ( 82. 6±2.9)% by a straight channel 7 mm in length and 1 mm in width. About 10% of sperm were found chemotactically responsive in our experiment, which is consistent with previous studies. Conclusion The combined evaluation of both sperm motility and chemotaxis was achieved for the first time, and the motile and chemotactically responsive sperm can be easily enriched on a lab-on-a-chip device to improve IVF outcome.