Figure 1:

Cellular forces can be measured using deformable materials. (A) A cell grown on the surface of a deformable material produces contractile forces that causes displacements on the surface of the material. Dashed lines represent the projected cell area before contraction. Arrows indicate the location, direction, and magnitude of the forces produced by a cell. (B) To measure cellular forces, elastic materials are often used which have a linear relationship between applied stress and observed strain. The slope of this linear relationship is referred to as the modulus of elasticity or Young’s Modulus (E). To achieve the same amount of strain in a soft (lower E, purple line) or stiff material (higher E, blue line), more stress needs to be applied to the stiff material. Once the Young’s Modulus of a material is known, one can measure deformation caused by cellular forces and infer the magnitude and direction of those forces.