Finite element simulation of mechanical tests of individual cells

Abstract

The threedimensional finite element (FE) model of eucaryotic cell presented in the paper is based on similar models published recently; it comprehends elements representing cell membrane, cytoplasm and nucleus, and a complex tensegrity structure representing cytoskeleton. In contrast to the previous models, this tensegrity structure consists of several parts. External and internal parts count 30 struts and 60 cables each and their corresponding nodes are interconnected by 30 radial members; these parts represent cortical, nuclear and deep cytoskeletons, respectively. This arrangement enables us to simulate the load transmission from the extracellular space via membrane receptors (focal adhesions) to the central part of the cell (nucleus, centrosome); this ability of the model was tested by simulation of some mechanical tests of isolated cells, in particular tension test with micropipettes, indentation test and magnetic tweezer test. Although material properties of components have been defined as realistic as possible on the base of the mechanical tests with vascular smooth muscle cells, they were not identified in fact and are not unique probably. However, simulations of the tests have shown the ability of the model to simulate the global load-deformation response of the cell under various types of loadings, as well as several substantial global features of the cell behaviour, e.g. “at a distance effect”, non-linear stiffening with increasing load, or linear dependence of stiffness on increasing prestrain.