Studies on cell separation with inertial microfluidics are often carried out with solid particles initially. When this condition is applied for actual cell separations, the efficiency typically becomes lower because of the polydispersity and deformability of cells. Therefore, the understanding of deformability-induced lift force is essential to achieve highly efficient cell separation. We investigate the inertial focusing positions of viscous droplets in a triangular channel while varying Re, deformability, and droplet size. With increasing Re and decreasing droplet size, the top focusing position splits and shifts along the sidewalls. The threshold size of the focusing position splitting increases for droplets with larger deformability. The overall path of the focusing position shifts with increasing Re also has a strong dependency on deformability. Consequently, droplets of the same size can have different focusing positions depending on their deformability. The feasibility of deformability-based cell separation is shown by different focusing positions of MCF10a and MCF7 cells.

中文翻译：

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三角形通道中惯性聚焦位置的变化取决于液滴的可变形性和大小。

惯性微流体对细胞分离的研究通常最初是用固体颗粒进行的。当将此条件应用于实际的细胞分离时，由于细胞的多分散性和可变形性，效率通常会降低。因此，了解可变形性引起的升力对于实现高效细胞分离至关重要。我们研究了三角形通道中粘性液滴的惯性聚焦位置，同时改变了Re，可变形性和液滴尺寸。随着Re的增加和液滴尺寸的减小，顶部聚焦位置沿侧壁分裂并移动。对于具有较大可变形性的液滴，聚焦位置分裂的阈值大小增加。聚焦位置的总体路径随Re的增加而变化，也与变形能力密切相关。因此，相同大小的液滴可根据其变形能力而具有不同的聚焦位置。MCF10a和MCF7细胞的不同聚焦位置显示了基于可变形性细胞分离的可行性。