Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, 100084 China.
Lab Chip. 2021 Jan 21;21(2):310-318. doi: 10.1039/d0lc00845a. Epub 2021 Jan 14.
In recent decades, humans have faced greater challenges in reproduction. Assisted reproductive technology is the most prominent approach for addressing this problem. Current clinical screening methods simply consider the motility or morphology of the sperm. However, as the spermatozoa need to navigate over a long distance in the female reproductive tract and survive the natural screening processes therein, these methods are imperfect. Many approaches have been undertaken to study the chemotaxis and thermotaxis navigation behavior of spermatozoa, but few of these have involved integrated screening that considers motility, chemotaxis, and thermotaxis based on the biological environment of the human body. Current routine sperm evaluation techniques are inadequate and fail to simultaneously provide conclusive evidence for the thermotactic and chemotactic characteristics of sperm. Thus, such screening of functional spermatozoa will be an advancement in assisted reproduction. In this study, we developed a fully integrated biomimetic microfluidic system for screening sperm for their characteristics when exposed to temperature and chemical gradients. Based on our results, we showed that spermatozoa were attracted by temperature and chemical gradients in the physiological range. Moreover, we ascertained a suitable temperature gradient range for thermotaxis and statistically proved that the thermotactic and chemotactic responses are not linked. Here, we report the first quantitative study of functional sperm during thermotaxis and chemotaxis, and our analysis of the difference in motility caused by different conditions. More broadly, we foresee the clinical application of these biologically motivated parameters and characteristics in assisted reproduction in humans.
近几十年来，人类在生殖方面面临着更大的挑战。辅助生殖技术是解决这个问题的最突出方法。目前的临床筛选方法仅仅考虑精子的活力或形态。然而，由于精子需要在女性生殖道中长途导航并在其中的自然筛选过程中存活下来，这些方法并不完美。已经有许多方法被用于研究精子的趋化性和趋热性导航行为，但很少有方法涉及基于人体生物环境的基于运动、趋化性和趋热性的综合筛选。目前的常规精子评估技术不足，无法同时为精子的趋热性和趋化性特征提供确凿的证据。因此，对功能性精子的这种筛选将是辅助生殖领域的一项进步。在这项研究中，我们开发了一种完全集成的仿生微流控系统，用于筛选精子在温度和化学梯度下的特性。根据我们的结果，我们表明精子在生理范围内受到温度和化学梯度的吸引。此外，我们确定了适合趋热的温度梯度范围，并从统计学上证明了趋热和趋化反应之间没有关联。在这里，我们报告了第一个关于功能精子在趋热和趋化过程中的定量研究，以及我们对不同条件下运动差异的分析。更广泛地说，我们预见到这些受生物学启发的参数和特性在人类辅助生殖中的临床应用。
