Figure 3: Examples of engineering strategies used to study the effects of anisotropic versus isotropic cytoskeletal tension on cultured stem cells. Substrates that mimic (a) soft versus (d) stiff ECM induce differential fates in human embryonic stem cell-derived cardiomyocytes, due to differential patterns of focal adhesions and actin-myosin stress fibres (in green, nuclei in blue). Reprinted and adapted from [8] with permission from John Wiley and Sons. In rat neural progenitor stem cells, (b) nonpatterned substrates induce formation of cell protrusions oriented randomly, while (e) micropatterned surfaces that mimic the native presentation and orientation of ECM proteins to cells induce alignment of elaborated processes in the direction of the grooves. Reprinted and adapted from [9] with permission from Elsevier. In rat mesenchymal stem cells, ultraprecise microscaffolds (c) with pore dimension of 20 microns allow for cell migration and isotropic attachment to the internal 3D lattice, whereas (f) for pores below 10 microns in size, cell migration into the scaffold pores is limited, inducing cell spreading on the top surface of the micro-scaffold (dividing nuclei in pink, cytoskeletal actin in green). Reprinted and adapted from [10] with permission from Elsevier.