Geometrical constraints and physical crowding direct collective migration of fibroblasts

Migrating cells constantly interact with their immediate microenvironment and neighbors. Although studies on single cell migration offer us insights into the molecular and biochemical signaling pathways, they cannot predict the influence of cell crowding and geometrical cues. Using microfabrication techniques, we examine the influence of cell density and geometrical constraints on migrating fibroblasts. Fibroblasts were allowed to migrate on fibronectin strips of different widths. Under such conditions, cells experience various physical guidance cues including boundary effect, confinement and contact inhibition from neighboring cells. Fibroblasts migrating along the edge of the fibronectin pattern exhibit spindle-like morphology, reminiscent of migrating cells within confined space and high cell density are associated with increased alignment and higher speed in migrating fibroblasts.