Figure 6. Cyclic mechanical reinforcement of integrin α5β1 covalently linked to surface.
A, Schematic of covalent tethering of α5β1-Fc to mixed SAMs of alkanthiols using standard NHS/EDC chemistry. Compared to capturing α5β1-Fc by an anti-Fc (GG-7), covalently attaching α5β1-Fc to the substrate via chemical crosslinking prevented the integrin from dissociating from the substrate. B, Binding specificity. Data are presented as mean ± s.e.m.. C, Distributions of FN–α5β1 bond lifetimes measured at 5 pN without (black) or with (magenta) a cyclic force of 20-pN peak (points) and their model fits (curves). D, Distributions of FN–α5β1 bond lifetimes measured at 10 pN with 0.5 (black), 1.5 (red), 2.5 (green), and 3.5 (blue) force cycles (points) and their model fits (curves). E, Lifetimes of the longest-lived state deduced from fitting the lifetime distributions in C (pink) and D (matched colors) with a three-state model.