Figure 4.

Nonlinear mechanical properties determine cell fate. a) An overview of strain‐stiffening properties for different materials. Reproduced with permission.29 Copyright 2016, Nature Publishing Group. b) Cells can generate cell traction forces to actively stiffen fibrin gel. Reproduced with permission.30 Copyright 2013, Cell Press. The traction strain was quantified by measuring the displacements of embedded fluorescent beads inside the fibrin hydrogel (black lines). The elastic modulus was measured by real time rheology (red line). The blue curve shows elastic modulus for a pure fibrin gel without cells. c) An overview of stress‐relaxation properties for different materials (including hydrogels and tissues). Reproduced with permission.[[qv: 6b]] Copyright 2016, Nature Publishing Group. d) Hydrogels with faster stress relaxation property can promote cell spreading and proliferation. Reproduced with permission.[[qv: 6b]] Copyright 2016, Nature Publishing Group.