Figure 2.

Principle of a single cell traction force assay. A single cell spreads between and pull on two parallel glass microplates coated with fibronectin. Cell traction force is measured through the deflection d of a flexible plate of calibrated stiffness k; F = kd. The setup is equivalent to one where the cell would be compressing a spring of stiffness k. By using plates of different stiffness, we have recently investigated the effect of rigidity on the contractile activity at the cell scale, i.e., on the overall force F.