The mechanical properties of cells, such as leukocytes, in a diseased state differ from those of healthy cells, typically due to their microstructure. The deformability of the cells through a constrictive area is analyzed by the applied stress to the cell. This study investigates the relationship between the sample flow speed and distribution of captured leukocytes based on the cell deformability using a microfluidic device. The device comprises of microfilters that serve as the filtration mechanism. The microfilter gap size gradually decreases from 15 to 3 µm to facilitate the deformability-based separation. Leukocytes have various sizes; hence, they can be separated by microfilters directly from whole blood samples without any cell clogging, and they do not require sample pre-processing such as centrifugation or red blood cell lysis. The distribution of leukocytes captured by the microfilters with respect to the sample flow speed can be analyzed; at higher sample flow speeds of 6 µL/min, small leukocytes with a size of 7 µm could not be captured and they passed through the smallest microfilter gap size of 3 µm. For smaller leukocytes, such as lymphocytes, the distributions are mainly at gap sizes of 4 µm to 8 µm, with most of the lymphocytes captured at the 6 µm microfilter gap size. We conclude that the distribution of the cells captured during the filtration varies depending on the microfilter gap sizes, applied sample flow speed, cell sizes, and the ability of the cells to deform. The deformability imaging profiles of the sample could be developed from the images of the cell distribution, which might be useful for preliminary screening in the clinical applications. This work presents the development of a simple device for the study of cell deformability as the results provide a biophysical marker in high throughput and bulk sample analyses.

中文翻译：

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快速检查全血样本中白细胞变形能力的微流体装置

处于患病状态的细胞（如白细胞）的机械特性与健康细胞的机械特性不同，通常是由于其微观结构。通过向细胞施加应力来分析细胞通过狭窄区域的变形能力。这项研究基于使用微流体装置的细胞可变形性，研究了样品流速与捕获的白细胞分布之间的关系。该装置包括用作过滤机构的微过滤器。微型过滤器的间隙尺寸从15 µm逐渐减小到3 µm，以促进基于可变形性的分离。白细胞大小各异。因此，它们可以通过微滤器直接从全血样品中分离出来，而没有任何细胞阻塞，并且它们不需要样品预处理，例如离心或红细胞裂解。可以分析微滤器捕获的白细胞相对于样品流速的分布；在更高的6 µL / min样品流速下，无法捕获大小为7 µm的小白细胞，它们会通过最小的3 µm微型过滤器间隙。对于较小的白细胞，例如淋巴细胞，分布主要在4 µm至8 µm的间隙大小，而大多数淋巴细胞捕获在6 µm的微滤器间隙大小。我们得出的结论是，在过滤过程中捕获的细胞分布取决于微滤器间隙大小，应用的样品流速，细胞大小以及细胞变形的能力。样品的可变形性成像图可以从细胞分布的图像中得出，这可能对临床应用中的初步筛选有用。