Acquiring Uniaxial Stress-Strain Curve by Fast Finite Element Analysis for Characterization of Whole-Cell Elastic Property

[摘要] An understanding of whole-cell elastic property can provide insight into cellular response to mechanical loading. Hertz model is often used to extract the Young’s modulus from the atomic force microscopy (AFM) force indentation depth curve (F-D curve) for characterization of cell’s elastic property. However, Hertz model is only relatively accurate when the sample can be regarded as infinite half space and its material is linear elastic, which is contradictory with the fact that cell is usually very thin and cell’s elastic properties are considered to be highly nonlinear, especially when the deformation is very large. Finite element analysis can be used to handle the nonlinear elastic property and large deformation by using the hyperelastic model to model the cell material. However, previous studies have not demonstrated a convenient way to search for the model parameters that can fit the experimental data. In this paper, we put forward a method based on finite element analysis. Our new method adopts a general uniaxial stress-strain curve (associated with a hyperelastic model) to represent cell’s material and uses a recursive method to search for this uniaxial stress-strain curve by minimizing the difference between the experimental and simulated F-D curve. This new recursive approach not only offers a high match accuracy between the experimental and simulated F-D curve(error rate less than 5% is ready to be obtainable), but also minimizes the number of recursions in searching for the stress-strain curve(less than 10 recursions are enough for the good enough match in normal situation).

[发布机构] the University of Pittsburgh