The topographical switching of focal adhesion maturation sites and actin filament activation on the well-defined grid micropatterns

Securing robust cell adhesion between cells and biomaterials is one of key considerations for tissueengineering. However, the cell adhesion investigation by the biophysical effects such as topography or rigidity of substrates has only been recently reported. In this study, we examined the spatial property of focal adhesions by changing the height of micropatterns in two kinds of microtopography (grid and post) and the stiffness of the substrates. We found that the focal adhesion localization is highly regulated by topographical variation (height) of gird micropattens but not the rigidity of substrates or the function of actin cytoskeleton, although the latters strongly influence the focal adhesion size or area. In detail, the change of the height of the grid micropatterns results in the switching of focal adhesion sites; as the height increases, the localization of focal adhesion is switched from top to bottom areas. This study demonstrates that the localization of focal adhesion on well-defined micropatterned substrates is critically determined by the topographical variation in the micropatterns.