Evolution of Stresses at Cell-Gel Interfaces during Confined Interfacial Migration

Abstract

Cell migration at the interface of two substrates under confinement holds clinical significance as it is instrumental in morphogenesis and wound healing but has been insufficiently studied. The adhesions at the cell-gel interface are instrumental in deciding the fate of cell motility, viability and morphology. However, experiments have not been able to shed light into the evolution of stresses within the cells and at the interfaces. Therefore, a better understanding of the mechanics involved in such a process is necessary. The various components of the cell and both the gels were modelled as viscoelastic systems. We used finite element modelling to study the evolution of stresses and deformation within the cell and at the cell-gel interfaces. The cell is attached to an underlying soft gel substrate by focal adhesions (FAs), whereas, no adhesions are formed at the cell-stiff gel interface. The asymmetry in adhesion at the two cell-gel interfaces leads to an asymmetric stress state of the cell with relatively larger stress developing at the interface with stiff gel indicating higher actin density at this interface than at that with soft gel. This is validated by prior experiments. The location of FAs is found to play a decisive role in mechanotransduction as the FAs close to the region of protrusion are maximally stressed during motion but those farther away are scarcely engaged, which has also been demonstrated in prior experiments. An understanding of the stress evolution within the cell undergoing interfacial migration and at the interface can be potentially used to design wound healing tissue adhesives.