Cell Migration Driven by a Mechanical Stiffness Gradient

This paper reports the migration of cells along the gradient of mechanical stiffness when the cells are cultured on a flexible substrate with variable rigidity. The thickness difference of PDMS layer was used to create a stiffness gradient between a stiff (7 mum) and a soft (2 mum) region. A fabrication process was developed to minimize the effect of other factors such as height difference and surface chemistry variation that can affect the pattern of cell migration. A cultured embryonic carcinoma cells on the flexible substrate coated with fibronectin, and observed that most of cells were accumulated on the stiffer region. Patterns in various shapes and sizes with stiffness difference were tested to investigate the migratory behavior of the cells. The results suggest that our approach provides a key technology to study the mechanism of cell migration by durotaxis.