3D finite element analysis of uniaxial cell stretching: from image to insight

Abstract

Mechanical forces play an important role in many microbiological phenomena such as embryogenesis, regeneration, cell proliferation and differentiation. Micromanipulation of cells in a controlled environment is a widely used approach for understanding cellular responses with respect to external mechanical forces. While modern micromanipulation and imaging techniques provide useful optical information about the change of overall cell contours under the impact of external loads, the intrinsic mechanisms of energy and signal propagation throughout the cell structure are usually not accessible by direct observation. This work deals with the computational modelling and simulation of intracellular strain state of uniaxially stretched cells captured in a series of images. A nonlinear elastic finite element method on tetrahedral grids was applied for numerical analysis of inhomogeneous stretching of a rat embryonic fibroblast 52 (REF 52) using a simplified two-component model of a eukaryotic cell consisting of a stiffer nucleus surrounded by a softer cytoplasm. The difference between simulated and experimentally observed cell contours is used as a feedback criterion for iterative estimation of canonical material parameters of the two-component model such as stiffness and compressibility. Analysis of comparative simulations with varying material parameters shows that (i) the ratio between the stiffness of cell nucleus and cytoplasm determines intracellular strain distribution and (ii) large deformations result in increased stiffness and decreased compressibility of the cell cytoplasm. The proposed model is able to reproduce the evolution of the cellular shape over a sequence of observed deformations and provides complementary information for a better understanding of mechanical cell response.

Mechanical Stretching for Tissue Engineering: Two-Dimensional and Three-Dimensional Constructs

“…Matrix strain has been measured directly, or determined by using microscopy and finite element (FE) techniques. [38][39][40][41] Cells receive varying degrees of compressive strain in a direction perpendicular to the stretch axis dependent on the Poisson ratio of the membrane or scaffold. 42,43 Work in 3D FE has shown that the strain that cells actually receive can be much larger than that applied to the matrix due to variations in matrix microarchitecture.…”

Actuation means for the mechanical stimulation of living cells via microelectromechanical systems: A critical review

“…However, they are one of the most widespread option for ensuring the actuation of passive MEMS dedicated to the stimulation of cells. Thereby, positioning stages are conventionally used to actuate passive microstructures such as microplates (e.g., Thoumine et al, 1999;Desprat et al, 2006;Ferná ndez et al, 2006;Gladilin et al, 2007;Chan et al, 2008) or microindenters (e.g., Koay et al, 2003;Peeters et al, 2005;Sato et al, 2007).…”

Measuring Cell Adhesion Forces: Theory and Principles

“…Of course, this analysis requires that the cell is still connected to the cantilever after detachment from the surface. Another solution would be to covalently couple cells to the cantilever, e.g., using glutaraldehyde (35).…”