Mechanotaxis

Mechanotaxis refers to the directed movement of cell motility via mechanical cues (e.g., fluidic shear stress, substrate stiffness gradients, etc.).^[1][2][3] In response to fluidic shear stress, for example, cells have been shown to migrate in the direction of the fluid flow.^[1][4] Mechanotaxis is critical in many normal biological processes in animals, such as gastrulation,^[5] inflammation,^[6] and repair in response to a wound,^[7] as well as in mechanisms of diseases such as tumor metastasis.^[7]

A subset of mechanotaxis - termed durotaxis - refers specifically to cell migration guided by gradients in substrate rigidity (i.e. stiffness).^[2][8] The observation that certain cell types seeded on a substrate rigidity gradient migrate up the gradient (i.e. in the direction of increasing substrate stiffness) was first reported by Lo et al.^[9] The primary method for creating rigidity gradients for cells (e.g., in biomaterials) consists of altering the degree of cross-linking in polymers to adjust substrate stiffness.^[10][11] Alternative substrate rigidity gradients include micropost array gradients, where the stiffness of individual microposts is increased in a single, designed direction.^[8]