Under internal or external insults such as aging and oxidative stresses, cells are induced into a senescent state and stop cellular division permanently. As senescent cells (SnCs) accumulate, the regeneration capacity of biological tissue would be compromised, which has been found to be associated with a plethora of age-related disorders. Therefore, isolating SnCs becomes necessary. To address the lack of effective surface markers for SnCs isolation, a label-free microfluidic device was proposed in this paper, in which a spiral microchannel was deployed to isolate SnCs based on their size differences. We adopted a well-received cellular senescence model by exerting excessive oxidative stress to murine mesenchymal stem cells. This model was then validated through a series of SnCs characterizations including size measurement, p16INK4a expression level, senescence-associated beta-galactosidase, and doubling time. The senescence chip demonstrated an efficiency of 75% and viability over 85% at a flow rate of 5 ml/min. The average cell size from the inner outlet was 5 μm larger than that from the outer outlet. The isolated cells had a sixfold higher p16INK4a expression level. Overall, the chip had an area under curve of 0.719 in the receiver operating characteristic analysis, showing decent performance in sorting SnCs. By having the ability to perform size-based sorting at a high flow rate, such a microfluidic device can provide high-throughput and label-free isolation of SnCs. To further improve the isolation performance, the device can be modified to introduce additional physical biomarkers of SnCs such as stiffness. This device poses a good potential in purification for cytotherapy or estimation of biological age.

中文翻译：

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高通量和无标记的衰老小鼠间充质干细胞分离。

在诸如衰老和氧化应激之类的内部或外部侮辱下，细胞被诱导进入衰老状态并永久停止细胞分裂。随着衰老细胞（SnCs）的积累，生物组织的再生能力将受到损害，这已被发现与多种与年龄有关的疾病有关。因此，隔离SnCs是必要的。为了解决SnCs分离缺乏有效的表面标记的问题，本文提出了一种无标记的微流控设备，该设备中基于其大小差异部署了螺旋微通道来分离SnCs。我们通过对鼠的间充质干细胞施加过度的氧化应激，采用了广受好评的细胞衰老模型。然后通过一系列SnCs表征（包括尺寸测量，p16INK4a表达水平，衰老相关的β-半乳糖苷酶和加倍时间。衰老芯片在5 ml / min的流速下显示出75％的效率和超过85％的活力。内部出口的平均细胞大小为5 μ中号比从外出口大。分离的细胞具有较高的p16INK4a表达水平六倍。总体而言，在接收器工作特性分析中，该芯片的曲线下面积为0.719，显示出对SnCs进行分选的良好性能。通过具有以高流速执行基于大小的分选的能力，这样的微流体装置可以提供高通量和无标签的SnCs分离。为了进一步提高隔离性能，可以对设备进行修改，以引入SnCs的其他物理生物标记，例如硬度。该设备在细胞疗法纯化或生物学年龄估计方面具有良好的潜力。