细胞骨架

Details are presented for the formulation, fabrication, and mechanical characterization of mesoscopic freestanding polydimethylsiloxane (PDMS) elastomer membranes, 10.0 microm thick and 5.0 mm in diameter, used to probe the rheology of a living epithelial sheet. In what is described as a composite diaphragm inflation (CDI) experiment, freestanding PDMS membranes are utilized as substrates for the culture of a sheet of epithelial cells.

Abstract\n\t\t\t\t\n\t\t\t\t\tDetails are presented for the formulation, fabrication, and mechanical characterization of mesoscopic freestanding polydimethylsiloxane (PDMS) elastomer membranes, 10.0 μm thick and 5.0 mm in diameter, used to probe the rheology of a living epithelial sheet. In what is described as a composite diaphragm inflation (CDI) experiment, freestanding PDMS membranes are utilized as substrates for the culture of a sheet of epithelial cells.

细胞感知和响应周围微环境的机械信号的能力是组织工程和再生中的关键问题之一，然而，对既有细胞观察又有机械刺激的细胞进行基础研究具有挑战性，应以适当的微器件为基础。我们设计并制作了一个两层微流控芯片，可以同时观察活细胞和循环拉伸的弹性聚合物聚二甲基硅氧烷( PDMS )，表面修饰以增强细胞粘附。人间充质干细胞( hMSCs )的频率范围为0.00003 ~ 2Hz，振幅为2 %、5 %或10 %。初始随机取向的细胞在大于阈值的频率下被证实是垂直于拉伸方向的重取向，我们称之为临界频率( fc )，且临界频率fc与振幅有关。我们进一步引入了临界拉伸速率( Rc )的概念，发现该量可以统一频率和振幅依赖关系。本研究中Rc的倒数为8.3 min，与文献报道的肌动蛋白丝周转时间一致，提示细胞骨架内的超分子弛豫可能是细胞底层的机械性转导所致。基于单轴循环拉伸下的二维张拉整体模型的细胞重定向理论计算与我们的实验吻合较好。上述发现为生物材料在生物力学刺激下，临界频率和临界拉伸速率在细胞调控中的关键作用提供了新的认识。