Static and dynamic mechanics of cell monolayers: A multi-scale structural model

Epithelial monolayers act as a vital player in a variety of physiological activities, such as wound healing and embryonic development. The mechanical behavior of epithelial monolayers has been increasingly studied with the recent rapid development of techniques. Under dynamic loadings, the creep response of epithelial monolayers shows a power-law dependence on the time with an exponent larger than that of a single cell. Under static loadings, the elastic modulus of epithelial monolayers is nearly two orders of magnitude higher than that of a single cell. To date, there is a lack of a mechanical model that can describe both the dynamic and static mechanical responses of epithelial monolayers. Here, based on the structural features of cells, we establish a multi-scale structural model of cell monolayers. It is found that the proposed model can naturally capture the dynamic and static mechanical properties of cell monolayers. Further, we explore the effects of the cytoskeleton and the membrane moduli on the dynamical power-law rheological responses and static stress-strain relations of a single cell and cell monolayers, respectively. Our work lays the foundation for subsequent studies of the mechanical behavior of more complex epithelial tissues.