Effects of contact surface shape on lifetime of cellular focal adhesion

Abstract

As a means of better understanding cell-matrix adhesion, we consider the effects that the contact surface shape of a cellular focal adhesion has on its adhesion lifetime. An idealized model of focal adhesion is adopted in which two dissimilar elastic media are bonded together by an array of ligand/receptor bonds modeled as Hookean springs on a curved surface. The cluster of bonds is subjected to a constant applied tensile load F, and the distribution of traction forces on the individual bonds is assumed to obey the elasticity equations of continuous elastic media. The rupturing and rebinding of bonds are described by stochastic equations solved using the Monte Carlo method. The contact surface in the model is scaled by an optimal shape defined as the deformed surface profile of a planar elastic half-space that is subjected to a uniform pressure applied over the contact region with the total force equal to F. Our model shows that contact surface shape does have a substantial impact on adhesion lifetime. The model also shows that the adhesion lifetime becomes increasingly sensitive to variations in contact surface shape as the focal adhesion increases in size.