Force-versus-distance curve. Point A of the curve indicates the probe connects with the surface of the cells. From point A to B, the probe presses on the cell membrane and the opposing force generated along with increasing strain in the cell surface rises. At point B, the probe is ready to detach from the surface of the cell and no longer pushes against the membrane, so the opposing force reaches peak.
Chen et al. BMC Cell Biology 2013 14:22 doi:10.1186/1471-2121-14-22