Figure 4. Comparison of how cells pull and induce traction forces on hydrogels and microposts.

Cells bind to substrates via coupling to extracellular matrix proteins in focal adhesions. On both continuous hydrogel substrates and microposts, these focal adhesions occupy distinct areas of the material. Cell-binding area can be defined on hydrogels and micropost arrays by patterning of extracellular matrix proteins (and in addition by micropost geometry). The effective spring constant of hydrogels and microposts is based on contract area between the substrate and the cell exerting traction forces. Figure adapted with permission from [201].