Measuring single-cell water content non invasively and with high precision

总结 水是生物化学运作的介质。细胞内的水量决定了细胞的浓度 和分子拥挤程度的关系。因此，预计含水量将影响 几乎所有的细胞功能，从免疫监视到体内干细胞更新。也有严重的遗传性 由细胞膜上突变的水通道引起的疾病。尽管细胞内的水起着重要的作用 在细胞生理和疾病的内容，有没有直接和非侵入性的方法，测量多少 单个细胞或一群细胞（如类器官）所含的水。缺乏水含量测量 阻碍了我们理解正常和疾病状态下的细胞生理学， 在水含量受到干扰的疾病中可以调节细胞的水含量。在此，我们建议 开发一种新的方法，直接，非侵入性和精确地测量绝对和分数（v/v） 单个细胞或类器官的含水量。这种方法将使长期监测同一细胞 或在生长、分化或药物暴露期间的类器官。为了实现这一点，我们将整合总量和 干体积测量使用两个独立的方法，我们以前开发的。我们 所提出的方法将能够测量复杂和生物医学相关样品中的水含量， 作为免疫细胞和类器官，具有高通量并结合荧光标记物的检测。 这种方法将使新的基础和生物医学研究，将增加我们对水的理解 内容监管健康和疾病，并为药物发现提供新的平台。

SUMMARY Water is the medium in which biochemistry operates. The amount of water inside a cell defines the concentration of all biomolecules and the degree of molecular crowding. Consequently, water content is predicted to influence virtually all cell functions from immune surveillance to stem cell renewal in vivo. There are also severe genetic diseases caused by mutated water channels on cell membranes. Despite the fundamental role of cellular water content in cell physiology and diseases, there are no direct and non-invasive methods that measure how much water a single cell or a cluster of cells, such as an organoid, contains. This lack of water content measurements has prevented us from understanding cell physiology in normal and disease states, and from discovering drugs that can modulate cellular water content in diseases where water content is perturbed. Here, we propose to develop a new method that will directly, non-invasively and precisely measure the absolute and fractional (v/v) water content of a single cell or an organoid. This method will enable the long-term monitoring of the same cell or organoid during growth, differentiation or drug exposure. To achieve this, we will integrate total volume and dry volume measurements obtained using two independent approaches that we have previously developed. Our proposed method will enable water content measurements in complex and biomedically relevant samples, such as immune cells and organoids, with high throughput and in conjunction with detection of fluorescent markers. This method will enable novel basic and biomedical research that will increase our understanding of water content regulation in health and disease, and provide a new platform for drug discovery.