Instrument-dependent cadherin monolayer interactions.

We introduce two theoretical models for predicting forces between cadherin-coated sphere and plane. The first model is based on a continuum theory previously developed for the interaction of large objects embedded in liquids. The second model takes into account size effects, which are relevant in the cadherin measurements, as the size of the tip is frequently comparable to the size of geometrical features of the cadherin. We use the models to compare force-separation curves in atomic force microscopy and surface force apparatus.