Droplet-based microfluidics for single cell-omics

水在油中很容易形成液滴，提供了微型封闭环境，在这种环境中，水(水相)与油相分离。如果这些液滴是在非常小的通道中产生的(例如，人类头发的宽度)，那么液滴的大小可以与单个细胞的大小相媲美。通过使用最先在半导体行业建立的微制造技术，我们能够创建适当的微通道体系结构，可以创建包含细胞的可重现液滴(液滴的行为类似于非常小的试管)。然而，到目前为止，制造这种液滴的尝试被证明是困难的。目前，它们是不稳定的，会像它们形成时一样迅速地结合和消失。使用一项新技术，我们建议使用相同的两相(油和水)系统来创建具有结构涂层的液滴，以便一旦将细胞放置在液滴中，微环境就会稳定且寿命更长。用来制造这种液滴的技术将使我们能够改变涂层的性质，使它们可以被认为是“智能的”。换句话说，通过设计涂层的化学成分，我们可以决定哪些分子进入微滴。有趣的是，我们还可以在液滴壁上引入纳米级传感器，来报告细胞的代谢状态。最后，我们将创建这种结构化液滴的阵列，以便可以方便地存储和分析许多单个细胞，并最终用于寻找和测试新药的过程。

Water will readily form droplets in oil, providing miniature enclosed environments, in which the aqueous (water phase) is separate from the oil phase. If these droplets are created in very small channels (the width of a human hair, for instance), then the size of the droplets can be comparable to that of individual single cells. By using the techniques of microfabrication, first established within the semi-conductor industry, we are able to create appropriate microchannel architectures that can create reproducible droplets that contain cells (the droplets behave like very small test tubes). However, to date, attempts to make such droplets have proved difficult. Currently they are unstable and will coalesce and disappear as rapidly as they form. Using a new technology, we propose to use the same two phase (oil and water) systems to create droplets with a structured coat, so that once the cells have been placed within the droplet, the micro-environment is stable and long lived. The techniques used for making such droplets will enable us to change the nature of the coating so that they can be considered 'intelligent'. In other words, by engineering the chemical composition of the coating, we can decide which molecules enter the micro-droplet. Intriguingly, we can also introduce nanometre scale sensors within the droplet wall that can report upon the metabolic state of the cell. Finally, we will create arrays of such structured droplets so that many single cells can be stored and analysed readily, and ultimately used in the process of finding and testing new medicines.