Figure 6.

PMA does not increase traction force generation on stiff substrates. Mean (and SEM) of RMS tractions ($T_{\mathit{RMS}}$), traction maxima ($T_{\mathit{Max}}$), and displacements of neutrophils from healthy donors seeded on polyacrylamide gels with a Young’s modulus of either 1.5 kPa (n = 70) (a–c) or 10 kPa (n = 105) (d–f). Cells were allowed to attach and settle, and then imaged before stimulation (“Unstim.”). Cells were then treated with 20nM PMA and were imaged 5 min post-addition and 30 min post-addition of PMA. Tractions were computed using the finite element method in Abaqus, and displacement heatmaps were generated for two representative cells at 30 min (c,f). Scale bars are 10 μm, and the white contours represents the boundary of the cell edge. Analyzed using paired Student’s t-test comparing each 5 min timepoint to the unstimulated timepoint and comparing each 30 min timepoint to the unstimulated timepoint, *p < 0.05.