Figure 4.

(A) The high swelling ratio Q results in a large population of migrating cells which, in MMP-sensitive gels (white triangles), is due to mostly proteolytic matrix remodeling and in MMP-insensitive gels (gray diamonds) due to physically controlled cell migration. With decreasing swelling ratios, the migrating population decreases. (B) In soft matrices, almost all the cells migrate in MMP-sensitive and MMP-insensitive gels. By increasing the stiffness, migration ceases and only cells in MMP-sensitive substrates can migrate.