Hefei National Research Center for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
Lab Chip. 2024 Oct 9;24(20):4827-4842. doi: 10.1039/d4lc00515e.
Sperm capture techniques that immobilize sperm to halt their motility are essential for the long-term analysis of individual sperm. These techniques are beneficial in assisted reproductive technologies such as intracytoplasmic sperm injection (ICSI) by allowing selective screening of sperm. However, there is a notable lack of high-throughput and non-destructive sperm capture methods that allow the flagellum to beat freely, which is crucial for accurately reflecting the behavior of unfettered, freely swimming sperm. To bridge this gap, we introduce a novel microfluidic device specifically engineered to capture sperm without restricting flagellar motion. The design utilizes sperm's innate boundary-following behavior in both 3D and 2D environments to direct them into a capture zone. Once captured, the sperm head is restrained while the flagellum remains free to exhibit natural beating patterns. Utilizing this device, we explore the effects of hyperactivating agents, temperature, and their combined influence on the dynamics of bovine sperm flagella. The unrestricted flagellar motion offered by our device yields two prominent advantages: it mirrors the flagellar behavior of free-swimming sperm, ensuring research findings are consistent with natural sperm activity, and it prevents imaging overlap between the flagellum and the capture structures, simplifying the automation of flagellar tracking and analysis. This technological advancement facilitates the collection of waveform parameters along the entire flagellum, addressing inconsistencies that have arisen in previous research due to differing measurement sites, and enabling precise extraction of sperm behavioral properties.
精子捕获技术可使精子固定以停止其运动，对于个体精子的长期分析至关重要。这些技术在辅助生殖技术中非常有益，例如胞浆内精子注射（ICSI），可允许对精子进行选择性筛选。然而，目前缺乏高通量且非破坏性的精子捕获方法，这些方法可以使鞭毛自由摆动，这对于准确反映不受束缚的自由游动精子的行为至关重要。为了弥补这一差距，我们引入了一种新颖的微流控设备，专门设计用于捕获精子而不会限制鞭毛运动。该设计利用精子在 3D 和 2D 环境中的固有边界跟随行为，将其引导至捕获区域。一旦捕获，精子头被限制，而鞭毛仍然可以自由展示自然的摆动模式。利用该设备，我们研究了超激活剂、温度及其对牛精子鞭毛动力学的综合影响。我们的设备提供的不受限制的鞭毛运动具有两个突出的优点：它反映了自由游动精子的鞭毛行为，确保研究结果与自然精子活动一致，并且它防止了鞭毛和捕获结构之间的成像重叠，简化了鞭毛跟踪和分析的自动化。这项技术进步有助于沿着整个鞭毛收集波形参数，解决了由于不同的测量部位而在前一项研究中出现的不一致性问题，并能够精确提取精子行为特性。
