On the role of elasticity in focal adhesion stability within the passive regime

Within a purely mechanical setting, we investigate the behavior, up to full decohesion, of a system modeling the interactions exchanged between focal adhesions and extra-cellular matrix in the passive regime. In our work, decohesion is described as a homogenized effect of low scales events leading to the rupture of the molecular bonds between integrin receptors and the extra-cellular matrix ligands. We propose a simple three-layers scheme of this mechanical system and, based on a Griffith-like approach, we analytically describe the transition from an elastic regime to the nucleation of a decohesion front, up to full decohesion. We focus our attention on the important role played by elasticity and deduce how the relative stiffness of the layers modulates the decohesion behavior, with the system undergoing a ductile–fragile detachment transition. The comparison with known experimental results on focal adhesions and DNA shear denaturation supports the effectiveness of the proposed model in predicting the mechanical behavior of decohesion phenomena in biological systems. Interestingly, we show the possibility of predicting focal adhesion lengths distribution based on the obtained force saturation as the focal adhesion dimension is increased theoretically deduced.