Atomic force microscopy and proteins.

This review briefly introduces the principles of atomic force microscopy (AFM) applied to protein samples. AFM provides three-dimensional surface images of the proteins with high resolution. The advantage of AFM for protein studies is that AFM can visualize directly the molecule under physiological conditions without previous treatment. AFM operated in the force-spectroscopy mode is now a widespread technique, often used to investigate ligand receptor interactions with the goal of measuring forces at the individual molecule level.