Fig. 4: FEM modeling of C. elegans embryo indentation experiments.
From: Force microscopy of the Caenorhabditis elegans embryonic eggshell
a A spheroidal, fluid-filled elastic shell is used as model for indentation simulations and data fitting. Eggshell deformation and resulting membrane stress upon indentation by a spherical indenter are shown for Δz = 15 µm (tip radius rind = 1 µm, shell thickness t = 300 nm, shell modulus Eshell = 0.12 GPa, pint = 1.6 × 105 Pa). The initial embryo shape in the relaxed state is indicated by gray lines (egg length l = 50 µm, width w = 35 µm). b 3-D representation of the simulated pint-Δz-Eshell parameter space. pint, the internal egg pressure that builds as a function of the indentation depth Δz, is an important parameter required for accurate fitting of the experimental Fz(Δz) curves. c Simulated and interpolated Fzsim-Δz-Eshell parameter space. The total force Fzsim exerted on the micro-indenter by the eggshell comprises an elastic membrane component and the force related to the internal egg pressure pint
