What Forces Does Cell Traction Force Microscopy Measure?
It is probably fair to say that the field of cell mechanics emerged with the pioneering work of Harris et al. [1], who observed that cells grown on thin silicone sheets generated wrinkling patterns — unfortunately, quantifying the forces at the cellular level was virtually impossible with their system. Almost two decades later, the study of cell mechanics began in earnest when Pelham and Wang [2] introduced a more rigorous method for quantifying individual cell-generated forces that quickly became known as cell traction force microscopy (CTFM), some form of which is now used in cell mechanics labs around the world. The basic idea underlying the original CTFM method is that the forces generated by cells can be calculated by solving an inverse problem for the displacement field experimentally measured by tracking microspheres embedded in a thin elastic substratum (typically polyacrylamide gel) on which the cells are cultured.