Cell migration and polarity on microfabricated gradients of extracellular matrix proteins

This paper explores the effects of the surface density and concentration profiles of extra cellular matrix proteins on the migration of rat intestinal IEC-6 cells. Microfluidic devices were used to create linear, immobilized gradients of laminin. This study investigated both the impact of the steepness and local concentrations on the directedness of cell migration. The bulk concentrations of proteins in the feed streams in the mixing device determined the gradient profile and the local concentration of laminin in the device. Two sets of gradients were used to explore cell migration directedness: (i) gradients with similar change in local concentration, i.e., the same gradient steepness, and (ii) different gradients with similar local concentrations. Cells migrated up the gradients, independent of the steepness of the gradients used in this study. At the same local laminin concentration, the migration rate was independent of the gradient steepness. However, cell directedness decreased significantly at high laminin densities.