基于微管道的精子活力与化学趋向性筛选装置

Integration of sperm motility and chemotaxis screening with a microchannel-based device

目的 精子筛选是IVF的一项关键步骤.目前临床上使用上游法来挑选有活力的精子进行后续操作.然而,除了活力以外,其他参数如顶体反应能力、化学趋向性、温度趋向性等也是精子健康的重要指标.为了同时筛选精子的活力和化学趋向反应,我们设计并制作了一款微器件,使用直管道连接双分叉管道来模拟女性生殖道.方法 我们对直管道的长度和宽度进行优化来筛选活力精子.我们有选择性地将卵丘细胞种植在双分叉管道的其中一侧来形成化学梯度.我们用游向不同分叉管道的精子数量比例来表征精子的化学趋向性.结果 长7 mm、宽1 mm的管道可将精子活力从（58.5±3.8）%提高到（82.6±2.9）%.我们的试验证实约有10%的精子具有化学趋向能力,这一比例和以往的研究相一致.结论 我们第一次在微装置上同时实现了精子活力和化学趋向性的评估,具有良好活力和化学趋向能力的精子可以被富集出来以改善后续IVF的结果.

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.