Stress and strain stiffening: Scatter plot of tentry versus εmax/Δp for 19,991 K562 cells as in Fig. 1c. (Black squares connected by red lines) Median values of tentry versus εmax/Δp for different pressure and strain bins with at least 250 cells in each bin, with a strain bin width of 0.03, a pressure bin width of 50 Pa, and median pressure and strain values as indicated by the numbers next to the grid lines. (Black grid) Fit of Eq. 1 to the binned data, with stress stiffening according to E = E0 + c1 Δp. Fit parameters are E0 = 58 Pa, c1 = 1.11 Pa−1, and β = 0.07. To see this figure in color, go online.