Fig. 3.

Discrete fiber network simulation shows that cross-link breakage leads to fiber recruitment. (A) Tensile forces generated by cellular contraction leads to the breakage of the fiber cross-links, which allows the cell to recruit more fibers. The fiber recruitment index increases when the cell contractile force increases and more cross-links break. The red circle denotes the outline of the cell. (B) Normalized fiber density as a function of cell contraction for networks with cross-links of different breaking strengths. (C) The cell induces large deformations to the soft network, whereas induced deformations are much smaller for the stiff and welded soft network (stronger cross-links). (D) Quantitative measurements verified that the welded soft network shows fiber recruitment index as stiff networks, indicating that strong cross-links inhibit fiber recruitment. C and D adapted with permission from ref. 16.