Evaluating the effective shear modulus of the cytoplasm in cultured myoblasts subjected to compression using an inverse finite element method.

In the present study, we employ our recently developed confocal microscopy-based cell-specific finite element (FE) modeling method, which is suitable for large deformation analyses, to conduct inverse FE analyses aimed at determining the shear modulus of the cytoplasm of cultured skeletal myoblasts, G(cp), and its variation across a number of cells. We calibrate these cell-specific models against experimental data describing the force-deformation behavior of the same cell type, which were published by Peeters et al. (2005b) [J. Biomech.]. The G(cp) calculated for five different myoblasts were contained in the range of 0.8-2.4 kPa, with the median value being 1 kPa, the mean being 1.4 kPa, and the standard deviation being 0.7 kPa. The normalized sum of squared errors resulting from the fit between experimental and calculated force-deformation curves ranged between 0.12-0.73%, and Pearson correlations for all fits were greater than 0.99. Determining the mechanical properties of the cytoplasm through cell-specific FE will now allow calculation of cell stresses using cell-specific FE under various cell loading configurations, in support of experimental work in cellular mechanics.