Last year, Rief et al.
Brighter regions correspond to higher surface elevation or frictional force.
Data taken on a PicoSPM in our lab at ASU is shown in Figure 2. In this particular case, there was good reason to believe that the protein was attached to the surface in globular form. But in general, the experimenter cannot assume that the protein is in its native form. Imaging is required. Figure 4 shows a MAC Mode image of the Titin protein.