Haddadi Hamed, Naghsh-Nilchi Hamed, Di Carlo Dino
Department of Bioengineering, University of California at Los Angeles, 420 Westwood Plaza, Los Angeles, California 90095, USA.
Biomicrofluidics. 2018 Feb 5;12(1):014112. doi: 10.1063/1.5009037. eCollection 2018 Jan.
Label-free separation of viable cancer cells using vortical microfluidic flows has been introduced as a feasible cell collection method in oncological studies. Besides the clinical importance, the physics of particle interactions with the vortex that forms in a wall-confined geometry of a microchannel is a relatively new area of fluid dynamics. In our previous work [Haddadi and Di Carlo, J. Fluid. Mech. , 436-467 (2017)], we have introduced distinct aspects of inertial flow of dilute suspensions over cavities in a microchannel such as breakdown of the separatrix and formation of stable limit cycle orbits for finite size polystyrene particles. In this work, we extend our experiments to address the engineering-physics of cancer cell entrapment in microfluidic cavities. We begin by studying the effects of the channel width and device height on the morphology of the vortex, which has not been discussed in our previous work. The stable limit cycle orbits of finite size cancer cells are then presented. We demonstrate effects of the separatrix breakdown and the limit cycle formation on the operation of the cancer cell separation platform. By studying the flow of dilute cell suspensions over the cavities, we further develop the notion of the and the relative rate of cell accumulation as optimization criteria which connect the device geometry with the flow. Finally, we discuss the proper placement of multiple cavities inside a microchannel for improved cell entrapment.
利用涡旋微流体流动对活癌细胞进行无标记分离已被引入，作为肿瘤学研究中一种可行的细胞收集方法。除了具有临床重要性外，在微通道壁面受限几何结构中形成的涡旋与粒子相互作用的物理原理是流体动力学中一个相对较新的领域。在我们之前的工作[哈达迪和迪·卡洛，《流体力学杂志》，436 - 467(2017)]中，我们介绍了微通道中稀释悬浮液在腔体上的惯性流动的不同方面，例如有限尺寸聚苯乙烯颗粒的分界线破裂和稳定极限环轨道的形成。在这项工作中，我们扩展实验以解决癌细胞在微流体腔体中捕获的工程物理学问题。我们首先研究通道宽度和器件高度对涡旋形态的影响，这在我们之前的工作中尚未讨论。然后给出有限尺寸癌细胞的稳定极限环轨道。我们展示了分界线破裂和极限环形成对癌细胞分离平台运行的影响。通过研究稀释细胞悬浮液在腔体上的流动，我们进一步发展了“[此处原文缺失相关内容]”的概念以及细胞积累的相对速率，将其作为连接器件几何结构和流动的优化标准。最后，我们讨论在微通道内多个腔体的合适布局，以提高细胞捕获率。
