State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, People's Republic of China.
Author to whom any correspondence should be addressed.
Biofabrication. 2020 Sep 30;12(4):045032. doi: 10.1088/1758-5090/abb295.
While the microfluidic chips for cell stretching and real-time cell observations have so far been composed of three layers, the present work reports a two-layer one, which is, on the surface, not available due to the 'inherent' difficulty of unstable focusing on cells in the microscopic observation under the stretching operation, etc. Herein, this difficulty was overcome to a large extent, in the case of appropriate device parameters, which were determined based upon finite element analysis and orthogonal experimental design. The novel chip was fabricated and confirmed to work in frequency up to 2 Hz and stretching ratio up to 20%. We further performed uniaxial stretching experiments of human mesenchymal stem cells on an elastic polymer, polydimethylsiloxane, and the cells were found to be highly oriented perpendicular to the stretching direction. The short working distance on this simplified two-layer chip enabled clear observation of microtubules and stress fibers of cells under an optical microscope. We also tested radial stretching and gradient stretching as proofs of concept of the extendibility of this type of chip. Therefore, in spite of being simpler, the two-layer chip suggested in this study exhibited enhanced and versatile functions, and the present work has thus afforded a new methodology of fabrication of microfluidic chips for the study of cells on biomaterials under a mechanical stimulus.
虽然用于细胞拉伸和实时细胞观察的微流控芯片迄今为止由三层组成，但本工作报告了一种两层结构，由于在拉伸操作下微观观察中细胞的“固有”不稳定聚焦等困难，因此在表面上不可用。在这里，在适当的设备参数的情况下，在很大程度上克服了这一困难，这些参数是基于有限元分析和正交实验设计确定的。新型芯片被制造出来，并被证实可以在高达 2 Hz 的频率和高达 20%的拉伸比下工作。我们进一步在弹性聚合物聚二甲基硅氧烷上进行了人骨髓间充质干细胞的单轴拉伸实验，发现细胞高度定向于拉伸方向。在这个简化的两层芯片上较短的工作距离使得可以在光学显微镜下清晰地观察细胞的微管和应力纤维。我们还测试了径向拉伸和梯度拉伸，以验证这种类型的芯片的可扩展性。因此，尽管这种两层芯片更简单，但它表现出增强和多样化的功能，本工作为此提供了一种在机械刺激下研究生物材料上细胞的微流控芯片的新制造方法。
