Fig. 3.
Magnitude and orientation of traction stress along the edge of a monolayer. (A) A growing cell monolayer on μFSA (2 μm diameter, 4 μm center to center) observed by transmission microscopy (60× air objective). The edge of the monolayer is outlined by the white line. The white arrows indicate the resulting force applied on four consecutive posts along the edge (indicated by circles). The magnitude of these traction stresses is not uniform, but the orientation remains centripetal all along the edge. (B) Average traction stress versus distance from the edge. Equidistant posts from the edge are pooled together to calculate for each distance the corresponding average traction stress. Posts used to calculate the last point are further than 16 μm toward the interior of the monolayer of A.