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. Author manuscript; available in PMC: 2019 Jun 19.
Published in final edited form as: Nat Methods. 2018 Jun 18;15(7):491–498. doi: 10.1038/s41592-018-0015-1

Figure 2. AFM measurements.

Figure 2.

The measurements were conducted using sharp conical AFM probes, conospherical probes of radius 750nm, and spherical probes of radius 2500nm. (a) Schematics of the measurements of the cell mechanics. An AFM probe of well-defined geometry indents a cell along the vertical z-axis. (b) Force curves collected with AFM. Force F vs. vertical position z of the cell. Typical force curves for mechanically soft and hard samples are shown. (c) Average elastic moduli obtained with various AFM probes under different conditions (vertical indenting speed v and surrounding temperature T) are shown. The error bar indicates one standard deviation. (d, f, h) Raw AFM force data (F versus z) obtained with the sharp conical probes (d), the dull conospherical probe (semi-vertical angle ~22.5°) (f), and the spherical probes (h). (e, g, i) Corresponding histograms and cumulative probabilities of the elastic modulus obtained for indentation depths of 0–300nm. The appropriate models were used for each type of the AFM probes: the Sneddon model for the sharp conical probes (e), the Hertz model for the dull conospherical probe (g), and the spherical probes (i). Sample temperatures and indenting speeds are shown in the histograms. AFM measurements and measured cell sample size are summarized in Supplementary Table 2.