Raj A, Sen A K
Department of Mechanical Engineering, Indian Institute of Technology Madras Chennai-600036 India
RSC Adv. 2018 Jun 7;8(37):20884-20893. doi: 10.1039/c8ra02763c. eCollection 2018 Jun 5.
We report an experimental and theoretical investigation of the entry and passage behaviour of biological cells (HeLa and MDA-MB-231) in a constricted compliant microchannel. Entry of a cell into a micro-constriction takes place in three successive regimes: protrusion and contact (cell protrudes its leading edge and makes a contact with the channel wall), squeeze (cell deforms to enter into the constriction) and release (cell starts moving forward). While the protrusion and contact regime is insensitive to the flexibility of the channel, the squeeze zone is significantly smaller in the case of a more compliant channel. Similarly, in the release zone, the acceleration of the cells into the microconstriction is higher in the case of a more compliant channel. The results showed that for a fixed size ratio and , the extension ratio decreases and transit velocity increases with increase in the compliance parameter . The variation in the cell velocity is governed by force due to the cell stiffness as well as that due to the viscous dampening , explained using the Kelvin-Voigt viscoelastic model. The entry time = () (1 + ) ( ) and induced hydrodynamic resistance of a cell Δ / = () (1 + ) ( ) were correlated with cell size ratio , Young's modulus and compliance parameter , which showed that both entry time and the induced hydrodynamic resistance Δ are most sensitive to the change in the compliance parameter . This study provides understanding of the passage of cells in compliant micro-confinements that can have significant impact on mechanophenotyping of single cells.
我们报告了对生物细胞（HeLa和MDA - MB - 231）在狭窄的柔性微通道中的进入和通过行为进行的实验和理论研究。细胞进入微缩 constriction 会经历三个连续阶段：突出与接触（细胞伸出其前缘并与通道壁接触）、挤压（细胞变形以进入 constriction）和释放（细胞开始向前移动）。虽然突出与接触阶段对通道的柔韧性不敏感，但在更柔性的通道情况下，挤压区域明显更小。同样，在释放区域，在更柔性的通道情况下，细胞进入微 constriction 的加速度更高。结果表明，对于固定的尺寸比 和 ，延伸比 随着柔顺性参数 的增加而减小，传输速度 增加。细胞速度的变化由细胞刚度 以及粘性阻尼 引起的力控制，这是使用开尔文 - 沃伊特粘弹性模型来解释的。细胞进入时间 = () (1 + ) () 以及细胞的诱导流体动力阻力 Δ /= () (1 + ) () 与细胞尺寸比 、杨氏模量 和柔顺性参数 相关，这表明进入时间 和诱导流体动力阻力 Δ 对柔顺性参数 的变化最为敏感。这项研究提供了对细胞在柔性微约束中通过情况的理解，这可能对单细胞的机械表型分析产生重大影响。
