Atomic Force Microscopy of Viruses.

Atomic force microscopy (AFM) makes it possible to obtain images at nanometric resolution, and to accomplish the manipulation and physical characterization of specimens, including the determination of their mechanical and electrostatic properties. AFM has an ample range of applications, from materials science to biology. The specimen, supported on a solid surface, can be imaged and manipulated while working in air, ultra-high vacuum or, most importantly for virus studies, in liquid. The adaptability of AFM is also favored by the large variety of specimens of very different sizes that it can deal with, such as atoms, molecules, and molecular complexes including viruses and cells. AFM allows, in addition, the possibility to observe dynamics in real time. Indeed, AFM facilitates single molecule experiments enabling not only to see but also to touch the material under study (i.e., mechanical manipulations) and constitutes a fundamental source of information for materials characterization. In particular, the study of the mechanical properties of viruses and other biomolecular aggregates at the nanoscale is providing humongous information This helps to elaborate mechano-chemical structure/function models of complex protein aggregates, expanding and complementing the information obtained by other techniques.