FIGURE 3:

MCF-10A MECs sense the stiffness of the substrate underneath the EM grid and change their nanoscale architecture accordingly. (A) The statistical differences between the distributions of protrusion widths comparing cells adhered to grids placed on glass (bare^stiff and rBM^stiff conditions) or on a PA hydrogel of 75Pa elastic module (bare^soft and rBM^soft conditions) are highly significant, regardless of whether cells were plated on bare carbon or on rBM-coated carbon (see Supplemental Table S1 for significance levels and p-values). (B, C) Slices 2 nm thick through representative tomograms of cells plated on bare carbon under the stiff, B, and soft, C, conditions. Scale bars are 200 nm. (D) The statistical differences between the relative percentages of filled intracellular membrane-enclosed compartments when cells under the stiff and soft conditions are compared are highly significant, regardless of whether cells were plated on bare carbon or on rBM-coated carbon (see Supplemental Table S2 for significance levels and p-values). (E, F) Slices 2 nm thick through representative tomograms of cells plated on bare carbon under the stiff, E, and soft, F, conditions. Filled intracellular membrane-enclosed compartments are marked by yellow dots. Scale bars, 200 nm.