The geometric pattern of a pillared substrate influences the cell-process distribution and shapes of fibroblasts

Fibroblasts alter their shape, direction of movement, cytoskeleton arrangement, and focal contact when placed upon square array pillars. We prepared pillars of 1 μm diameter, separated by 3 μm, and having 1, 5, and 10 μm heights using substrates displaying identical surface chemistry. When cells seeded initially onto the tops of the pillars, fibroblasts subsequently were immobilized in situ by several pillars that visibly protruded through, but did not pierce, the cell bodies. The cytoplasma then migrated outward with long straight lamella along the interval of the pillars and formed several discrete attachment zones at their side walls - the value of their form index (FI) was as high as 35 - which altered the cellular shape entirely. Most of the cells interacted with the pillar substrate by spreading preferentially in a particular direction, but some of them had the ability to undergo coincident two-direction (x and y) migration; right-angle turn orientations led to the growth of dramatic cellular morphologies. Interestingly, this fibroblast's behavior variation was gradually in proportion to the pillar height of substrate. Our results confirm that cellular migration and cellular shape are both strongly affected by the geometry of the growth microenvironment.