The application of atomic force spectroscopy to the study of biological complexes undergoing a biorecognition process.

Atomic force spectroscopy (AFS) is one of the most promising and powerful tools to get information on biorecognition processes at single molecule resolution. AFS allows to measure forces acting between biomolecules undergoing biorecognition process with a picoNewton sensitivity in near-physiological conditions and without any labelling. The capability of AFS to provide detailed information about the kinetics and thermodynamics of a single pair of interacting biomolecules, besides complementing traditional biochemical approaches, offers the possibility to elucidate non-conventional aspects of biorecognition processes, such as rare events, transient phenomena, conformational changes and molecular heterogeneity. Despite its enormous capabilities and potentialities, AFS as applied to biomolecular interactions, has provided some ambiguous and controversial results in different experimental contexts. The present critical review describes, after an in-depth introduction to AFS and to the most used experimental and data analysis procedures, the more recent and rewarding ideas and advancements to overcome the main critical aspects faced in the investigation of biorecognition processes. Possible developments of AFS in applicative fields are briefly addressed (150 references).