Cells docking inside microfluidic devices is effective in studying cell biology, cell-based biosensing, as well as drug screening. Furthermore, single cell and regularly cells docking inside the microstructure of microfluidic systems are advantageous in different analyses of single cells exposed to equal drug concentration and mechanical stimulus. In this study, we investigated bottom wall microgrooves with semicircular and rectangular geometries with different sizes which are suitable for single cell docking along the length of the microgroove in x-direction and numerous cells docking regularly in one line inside the microgroove in a 3D microchannel. We used computational fluid dynamics to analyze the fluid recirculation area inside different microgrooves. The height of recirculation area in the bottom of microgroove could affect the cell’s attachment, and also materials delivery to attached cells, so the height of recirculation area may have optimum value. In addition, we analyzed the fluid drag force on cell movement toward the microgroove. This parameter was proportional to the fluid velocities in x and y directions in different microgrooves geometries. In different microgrooves’ geometries the fluid velocity in y-direction did not change, but the fluid velocity in x-direction decreased inside the microgroove. Therefore, the cell movement time inside the microgroove increased, and also the drag force in y-direction could push the cells toward the bottom due to the lower drag force in x-direction. The percentages of negative shear stress and average shear stress on the adhered cell surface were also calculated. The lower average shear stress, and negative shear stress around 50% on the cell surface were against cell detachment from the substrate. The results indicated that at the constant fluid inlet velocity and microchannel height, microgroove geometry and ratio of cell size to the microgroove size play pivotal roles in the cell initial adhesion to the substrate as well as the cell detachment.

中文翻译：

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底壁微槽对微流控装置内细胞对接的几何影响的计算研究

细胞对接在微流控装置内可有效研究细胞生物学、基于细胞的生物传感以及药物筛选。此外，单细胞和常规细胞对接在微流体系统的微结构内，在对暴露于相同药物浓度和机械刺激的单细胞进行不同分析时是有利的。在这项研究中，我们研究了具有不同尺寸的半圆形和矩形几何形状的底壁微槽，这些微槽适用于沿微槽长度的单细胞对接X-方向和许多细胞在 3D 微通道中的微槽内有规律地在一条线上对接。我们使用计算流体动力学来分析不同微槽内的流体再循环区域。微槽底部再循环区的高度会影响细胞的附着，也会影响到附着细胞的物质输送，因此再循环区的高度可能具有最佳值。此外，我们分析了细胞向微槽移动的流体阻力。该参数与流体速度成正比X和是的不同微槽几何形状的方向。在不同的微槽几何形状中，流体速度是的-方向没有改变，但流体速度在X- 方向在微槽内减小。因此，细胞在微槽内的运动时间增加，阻力也在增加。是的- 方向可以将细胞推向底部，由于较低的阻力X-方向。还计算了粘附细胞表面上的负剪切应力和平均剪切应力的百分比。细胞表面上较低的平均剪切应力和大约 50% 的负剪切应力防止细胞从基底上脱离。结果表明，在恒定的流体入口速度和微通道高度下，微槽几何形状和细胞尺寸与微槽尺寸的比值在细胞与基底的初始粘附以及细胞脱离中起关键作用。