Introduction In atomic force microscopy (AFM), a sharp tip is scanned over a sample while maintaining a constant interatomic force between atoms on the end of the tip and atoms on the surface of interest (1). Early implementation of AFM employed the contact mode of operation in which the repulsive force experienced by the tip was measured by recording the cantilever deflection. Under ambient conditions, these repulsive forces range from a few tens to hundreds of nanonewtons. The forces between the AFM tip and the sample cause pressures large enough to induce distortion, remove portions of the sample from the substrate, and even damage the tip. By scanning in a liquid, capillary forces are reduced, which decreases the forces between the tip and sample by orders of magnitude. Other forces such as contact pressures, however, can still lead to dulling of the AFM tip and deformation of soft biological samples.