Cell motility, contact guidance, and durotaxis.

Mechanical properties of the substrate play a vital role in cell motility. In particular, cells have been shown to migrate along aligned fibers in the substrate (contact guidance) and up stiffness gradients (durotaxis). Here we present a simple mechanical model for cell migration coupled to substrate properties, by placing a simulated cell on a lattice mimicking biopolymer gels or hydrogels. In our model cells attach to the substrate via focal adhesions (FAs). As the cells contract, forces are generated at the FAs, determining their maturation and detachment. At the same time, the cell was also allowed to move and rotate to maintain force and torque balance. Our model, in which the cells only have access to information regarding forces acting at the FAs, without a prior knowledge of the substrate stiffness or geometry, is able to reproduce both contact guidance and durotaxis.