Fig. 5
Analysis of actin stress fibers and paxillin patches of 3T3 fibroblasts incubated for 24 h on gels presenting collagen I. a Confocal images of paxillin (green), actin (blue) and the nucleus (pink) of 3T3 cells on 5 kPa elastic gels (top) and viscoelastic gels (bottom) with 50 µg/ml collagen I coating both forms of PAA. Scale bars = 20 µm, insets are magnification x3 of the dotted boxes. b Confocal images of paxillin (green), actin (blue) and nuclei (pink) of 3T3 cells incubated for 24 h on 5 kPa elastic gels (top) and viscoelastic gels (bottom), both with 50 µg/ml collagen I coating the crosslinked network of PAA. Scale bars = 20 µm, insets are magnification x3 of the dotted boxes. c Percentage of cells containing stress fibers on elastic and viscoelastic gels as a function of G” and the type of PAA presenting collagen I. Sample size: NHS 0 Pa n = 8 cells, NHS 500 Pa n = 13 cells, sulfoSANPAH 0 Pa n = 24 cells, sulfoSANPAH 500 Pa n = 34 cells. d Percentage of cells containing paxillin clusters as a function of G” and the type of PAA presenting collagen I. Sample size: NHS 0 Pa n = 8 cells, NHS 500 Pa n = 13 cells, sulfoSANPAH 0 Pa n = 24 cells, sulfoSANPAH 500 Pa n = 34 cells. e Average number of paxillin patches per cell as a function of the value of G” and the mode of presenting collagen I at the surface of the gel. Sample size: NHS 0 Pa n = 8 cells, NHS 500 Pa n = 13 cells, sulfoSANPAH 0 Pa n = 24 cells, sulfoSANPAH 500 Pa n = 34 cells. Error bars represent the standard error. f Average size of paxillin clusters as a function of the G” of the substrate and the mode of presenting collagen I to the cells. Sample size: NHS 0 Pa n = 8 cells, NHS 500 Pa n = 13 cells, sulfoSANPAH 0 Pa n = 24 cells, sulfoSANPAH 500 Pa n = 34 cells. ***Statistically significant differences with a p-value of <0.01, as calculated by non-parametric Tukey's tests
