This article presents an approach of microfluidic flow cytometry capable of continuously characterizing cytoplasmic viscosities of single cells. The microfluidic system consists of a major constriction channel and a side constriction channel perpendicularly crossing each other. Cells are forced to rapidly travel through the major channel and are partially aspirated into the side channel when passing the channel junction. Numerical simulations were conducted to model the time dependence of the aspiration length into the side channel, which enables the measurement of cytoplasmic viscosity by fitting the model results to experimental data. As a demonstration for high‐throughput measurement, the cytoplasmic viscosities of HL‐60 cells that were native or treated by N ‐Formylmethionine‐leucyl‐phenylalanine (fMLP) were quantified with sample sizes as large as thousands of cells. Both the average and median cytoplasmic viscosities of native HL‐60 cells were found to be about 10% smaller than those of fMLP‐treated HL‐60 cells, consistent with previous observations that fMLP treatment can increase the rigidity of white blood cells. Furthermore, the microfluidic system was used to process granulocytes from three donors (sample size >1,000 cells for each donor). The results revealed that the cytoplasmic viscosity of granulocytes from one donor was significantly higher than the other two, which may result from the fact that this donor just recovered from an inflammation. In summary, the developed microfluidic system can collect cytoplasmic viscosities from thousands of cells and may function as an enabling tool in the field of single‐cell analysis. © 2019 International Society for Advancement of Cytometry

中文翻译：

---

使用交叉收缩通道对单细胞细胞质粘度进行高通量表征的微流控细胞术。

本文介绍了一种能够连续表征单个细胞的细胞质粘度的微流控流式细胞术方法。微流体系统由相互垂直交叉的主收缩通道和侧收缩通道组成。细胞被迫快速穿过主通道，并在通过通道连接处时部分吸入侧通道。进行了数值模拟以模拟吸入侧通道长度的时间依赖性，从而通过将模型结果与实验数据拟合来测量细胞质粘度。作为高通量测量的证明，天然或经N处理的 HL-60 细胞的细胞质粘度-甲酰甲硫氨酸-亮氨酰-苯丙氨酸 (fMLP) 的量化样本量高达数千个细胞。发现天然 HL-60 细胞的平均和中值细胞质粘度都比 fMLP 处理的 HL-60 细胞小约 10%，这与先前观察到的 fMLP 处理可以增加白细胞的硬度一致。此外，微流体系统用于处理来自三个供体的粒细胞（每个供体的样本量 > 1,000 个细胞）。结果显示，一名供体的粒细胞的细胞质粘度显着高于其他两名，这可能是由于该供体刚刚从炎症中恢复过来。总之，开发的微流体系统可以从数千个细胞中收集细胞质粘度，并可以作为单细胞分析领域的一种支持工具。© 2019 国际细胞计量学促进会