Figure 2.

Normal force profiles normalized by the radius of curvature (R) as a function of the surface separation (D) between two avidin-bearing surfaces in pure water. Filled symbols are approaching profiles; empty symbols are receding profiles. Error bar represents uncertainty in the value of a datum point within a given run; scatter between different runs may be larger. Shaded area: interaction between an avidin-bearing surface and bare mica (from ref (43)); the arrows indicate jump into adhesive contact. Lower inset: schematic of an SFB, where K_s and K_n are the shear and the normal spring, respectively (K_s = 300 N/m and K_n = 137 N/m). Upper inset: schematic of two interacting avidin-bearing surfaces.