Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Lab Chip. 2024 Nov 19;24(23):5225-5237. doi: 10.1039/d4lc00428k.
Egg (oocyte) vitrification is the dominant method for preserving fertility for women of reproductive age. However, the method is typically performed by hand, requiring precise (∼0.1 to 10 μL) and time-sensitive (∼1 s) liquid exchange of cryoprotectants (CPA) around eggs as well as fine handling of eggs (∼100 μm) for immersion into liquid nitrogen (LN). Here, we developed a microfluidic platform for programmable vitrification. Our platform is based on a millimeter-sized hanging droplet inside which a given egg is suspended and subjected to liquid exchanges within seconds. After programmable exposures to CPA, the egg is extracted from the liquid-air interface of the droplet using a motorized fine-tip instrument and immersed into LN for vitrification. To benchmark our platform with the manual method, we vitrified over a hundred mouse eggs and found comparable percentages (∼95%) for post-vitrification survivability. In addition, our platform performs real-time microscopy of the egg thereby enabling future studies where its morphology may be linked to functional outcomes. Our study contributes to the ongoing efforts to enhance the automation of embryology techniques towards broader applications in reproductive medicine both for clinical and research purposes.
卵子（卵母细胞）玻璃化是保存育龄妇女生育能力的主要方法。然而，该方法通常是手动操作的，需要在卵子周围精确（∼0.1 至 10 μL）且对时间敏感（∼1 s）地进行保护剂（CPA）的液体交换，以及精细地处理卵子（∼100 μm）以浸入液氮（LN）中。在这里，我们开发了一种用于可编程玻璃化的微流控平台。我们的平台基于毫米大小的悬挂液滴，其中悬浮有一个给定的卵子，并在几秒钟内进行液体交换。在可编程暴露于 CPA 后，使用电动微调仪器从液滴的气-液界面提取卵子并浸入 LN 中进行玻璃化。为了将我们的平台与手动方法进行基准测试，我们对一百多个小鼠卵子进行了玻璃化处理，发现其玻璃化后存活率相当（∼95%）。此外，我们的平台对卵子进行实时显微镜检查，从而能够进行未来的研究，将其形态与功能结果联系起来。我们的研究有助于提高胚胎学技术的自动化水平，以便在临床和研究目的方面更广泛地应用于生殖医学。
