Lemmon Christopher A, Sniadecki Nathan J, Ruiz Sami Alom, Tan John L, Romer Lewis H, Chen Christopher S
Dept. of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA.
Mech Chem Biosyst. 2005;2(1):1-16.
The interplay of mechanical forces between the extracellular environment and the cytoskeleton drives development, repair, and senescence in many tissues. Quantitative definition of these forces is a vital step in understanding cellular mechanosensing. Microfabricated post array detectors (mPADs) provide direct measurements of cell-generated forces during cell adhesion to extracellular matrix. A new approach to mPAD post labeling, volumetric imaging, and an analysis of post bending mechanics determined that cells apply shear forces and not point moments at the matrix interface. In addition, these forces could be accurately resolved from post deflections by using images of post tops and bases. Image analysis tools were then developed to increase the precision and throughput of post centroid location. These studies resulted in an improved method of force measurement with broad applicability and concise execution using a fully automated force analysis system. The new method measures cell-generated forces with less than 5% error and less than 90 seconds of computational time. Using this approach, we demonstrated direct and distinct relationships between cellular traction force and spread cell surface area for fibroblasts, endothelial cells, epithelial cells and smooth muscle cells.
细胞外环境与细胞骨架之间的机械力相互作用驱动了许多组织的发育、修复和衰老。对这些力进行定量定义是理解细胞机械传感的关键一步。微制造柱阵列探测器（mPADs）可在细胞黏附于细胞外基质期间直接测量细胞产生的力。一种用于mPAD柱标记、体积成像以及柱弯曲力学分析的新方法确定，细胞在基质界面施加的是剪切力而非点力矩。此外，通过使用柱顶部和底部的图像，可以从柱的挠度中准确解析出这些力。随后开发了图像分析工具，以提高柱质心定位的精度和通量。这些研究产生了一种改进的力测量方法，该方法具有广泛的适用性，并且使用全自动力分析系统执行起来简洁明了。新方法测量细胞产生的力时误差小于5%，计算时间少于90秒。使用这种方法，我们证明了成纤维细胞、内皮细胞、上皮细胞和平滑肌细胞的细胞牵引力与扩展的细胞表面积之间存在直接且明显的关系。
