Figure 4
Cellular traction forces positively correlate with substrate rigidity. (A) Traction force maps for SKOV-3 cells plated on FN-coated, fluorescent nanosphere-functionalized hydrogels were generated using Particle Image Velocimetry (PIV) and Fourier-Transform Traction Cytometry (FTTC) plugins for ImageJ. Phase contrast images (top) and traction force maps (middle and bottom) shown for representative cells adhered to gels of the indicated of the indicated Young’s modulus values. Traction force maps are shown with both local (middle) and global (bottom) scaling to highlight differences in traction forces across substrate rigidity. (B–D) Maximum traction (B), mean traction (C), and total cell strength were measured for cells adhering to hydrogels of each elastic modulus. Graphs depict all of the data points (green symbols), with box & whisker plots showing maximum & minimum values (whiskers), the 25th to 75th percentiles (box), and the median value (box line). (n = 15, 12, and 18 cells from 3 experiments for 3, 25, and 125 kPa samples, respectively; *p < 0.0001; #p = 0.007; §p = 0.0037; †p = 0.002; n.s. = not significant).
