ABSTRACT
Orthogonally functionalized nanopatterend surfaces presenting discrete domains of fibronectin ranging from 92 to 405 nm were implemented to investigate the influence of limiting adhesion site growth on cell migration. We demonstrate that limiting adhesion site growth to small, immature adhesions using sub-100 nm patterns induced cells to form a significantly increased number of smaller, more densely packed adhesions that displayed few interactions with actin stress fibers. Human umbilical vein endothelial cells exhibiting these traits displayed highly dynamic fluctuations in spreading and a 4.8-fold increase in speed compared to cells on nonpatterned controls. As adhesions were allowed to mature in size in cells cultured on larger nanopatterns, 222 to 405 nm, the dynamic fluctuations in spread area and migration began to slow, yet cells still displayed a 2.1-fold increase in speed compared to controls. As all restrictions on adhesion site growth were lifted using nonpatterned controls, cells formed significantly fewer, less densely packed, larger, mature adhesions that acted as terminating sites for actin stress fibers and significantly slower migration. The results revealed an exponential decay in cell speed with increased adhesion site size, indicating that preventing the formation of large mature adhesions may disrupt cell stability thereby inducing highly migratory behavior.
