An AFM probe with a spherical tip of radius indents a cell by when the applied force…

PHYSICS · Subjective · Fermi University Physics · Fluids & Continuum Physics · Biophysics & Medical Physics · Macromolecules, membranes and cell architecture

Forces, Machines and Signals, Ch Filaments, networks and the mechanics of whole cells

Problem

An AFM probe with a spherical tip of radius

R = 5.0\,\mathrm{\mu m}

indents a cell by

\delta = 800\,\mathrm{nm}

when the applied force reaches

F = 2.0\,\mathrm{nN}

. Treat the cell as an incompressible elastic half-space with Poisson's ratio

\nu = 0.5

and use the Hertz relation

F = \dfrac{4}{3}\dfrac{E}{1-\nu^2}\sqrt{R}\,\delta^{3/2}

. Find the cell's Young's modulus

E

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