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Since its introduction in the early 1980’s (Binnig et al., 1986), scanning probe microscopy (SPM) has shown its huge potential for the investigation of the matter at the micro-and nano-scale. In the following years, many variants have been introduced, exploiting electrostatic, magnetic or van der Waals-like forces acting between the sample surface and the probe. In the present chapter, we will be concerned with the latter, also known as atomic force microscopy (AFM). The heart of an atomic force microscope is a sharp tip attached to the extremity of a flexible cantilever, that interacts with the sample surface while the sample is scanned under the tip. The interaction forces between the tip and the sample cause the bending of the cantilever. When the sample is scanned under the tip, the tiny movements of the cantilever are detected by an optical lever system (a device for magnifying small angular displacements of a rotating body, exploiting the reflection of a fixed laser beam over a small mirror attached to the body) producing a spot of light whose position is measured, and they are used as the basis to reconstruct a pseudo-3D image of the sample surface. An atomic force microscope offers the possibility to operate in many different modes (namely: contact, non-contact and intermittent-contact modes), making this technique extremely versatile as it can be adapted to many classes of materials, from the solid state to the biological molecules. According to the sample stiffness, one can adopt the most suitable operating mode in order to reduce or even prevent any damage of the observed specimen.Nowadays, AFM has proven as an essential tool for the …
Publication date: 
7 Mar 2012

Michele Giocondo, Said Houmadi, Emanuela Bruno, Maria P De Santo, Luca De Stefano, Emmanuelle Lacaze, Sara Longobardi, Paola Giardina

Biblio References: 
Atomic Force Microscopy Investigations into Biology-From Cell to Protein