Figure 3.

AFM-based deformation of HeLa cells. (a) A scheme of data analysis workflow is given. (b) Cells in mitotic arrest were confined through a wedged cantilever (schematic: green, microtubules; violet, chromosomes). Oscillatory cell height modulations are applied at decreasing mean cell heights. (c) Exemplary force and cantilever height output at f = 0.1 Hz is shown. (d) Values of cortical tension and cell surface area associated with (c) were calculated from force and cantilever height as described before in (2). (e) Exemplary effective elastic moduli of cell cortices versus normalized cell heights is shown. Dashed lines show a fit according to Eq. 5 with fit parameters K_B and α. Uncertainties of estimated moduli because of sinusoidal fitting of output tension data are estimated to be ≤5%. (f) Normalized effective elastic moduli (K/K_B −1)/α of all cells measured at f = 0.1 Hz is shown. The phenomenological dependence predicted by Eq. 5 is captured by the solid black line. Different colors represent different cells. To see this figure in color, go online.