The impingement of a submerged, liquid jet onto a cell-covered surface allows assessing cell attachment on surfaces in a straightforward and quantitative manner and in real time, yielding valuable information on cell adhesion. However, this approach is insufficiently characterized for reliable and routine use. In this work, we both model and measure the shear stress exerted by the jet on the impingement surface in the micrometer-domain, and subsequently correlate this to jet-induced cell detachment. The measured and numerically calculated shear stress data are in good agreement with each other, and with previously published values. Real-time monitoring of the cell detachment reveals the creation of a circular cell-free area upon jet impingement, with two successive detachment regimes: 1), a dynamic regime, during which the cell-free area grows as a function of both the maximum shear stress exerted by the jet and the jet diameter; followed by 2), a stationary regime, with no further evolution of the cell-free area. For the latter regime, which is relevant for cell adhesion strength assessment, a relationship between the jet Reynolds number, the cell-free area, and the cell adhesion strength is proposed. To illustrate the capability of the technique, the adhesion strength of HeLa cervical cancer cells is determined ((34 ± 14) N/m2). Real-time visualization of cell detachment in the dynamic regime shows that cells detach either cell-by-cell or by collectively (for which intact parts of the monolayer detach as cell sheets). This process is dictated by the cell monolayer density, with a typical threshold of (1.8 ± 0.2) × 109 cells/m2, above which the collective behavior is mostly observed. The jet impingement method presents great promises for the field of tissue engineering, as the influence of both the shear stress and the surface characteristics on cell adhesion can be systematically studied.
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机译:将浸没的液体射流撞击到细胞覆盖的表面上,可以以直接,定量的方式实时地评估表面上的细胞附着,从而获得有关细胞粘附的有价值的信息。但是,这种方法的特征不足以可靠和常规使用。在这项工作中,我们既模拟并测量了射流在微米域中撞击表面上施加的剪切应力,随后将其与射流诱导的细胞脱离联系起来。测得的和通过数字计算得出的剪切应力数据彼此之间以及与先前发布的值之间具有很好的一致性。实时监测细胞脱离情况,揭示了喷射撞击后形成的圆形无细胞区域,并具有两个连续的脱离机制:1)动态机制,在此期间,无细胞区域随最大值的增加而增长射流施加的剪切应力和射流直径;其次是2),是一个稳定的方案,无细胞区域没有进一步的发展。对于与细胞粘附强度评估有关的后一种方案,提出了射流雷诺数,无细胞面积和细胞粘附强度之间的关系。为了说明该技术的功能,确定了HeLa宫颈癌细胞的粘附强度((34±14)N / m 2 sup>)。动态状态下细胞分离的实时可视化显示,细胞可以逐个细胞或整体分离(单层完整部分作为细胞片分离)。此过程由细胞单层密度决定,典型阈值为(1.8±0.2)×10 9 sup> cells / m 2 sup>,在该阈值以上通常观察到集体行为。喷射撞击法为组织工程领域提供了广阔的前景,因为可以系统地研究剪切应力和表面特性对细胞粘附的影响。
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