Binning, atomic force microscopy

Experimental techniques based on the application of mechanical forces to single molecules in small assemblies have been applied to study the binding properties of biomolecules and their response to external mechanical manipulations. Among such techniques are atomic force microscopy (AFM), optical tweezers, biomembrane force probe, and surface force apparatus experiments (Binning et al., 1986 Block and Svoboda, 1994 Evans et ah, 1995 Israelachvili, 1992). These techniques have inspired us and others (see also the chapters by Eichinger et al. and by Hermans et al. in this volume) to adopt a similar approach for the study of biomolecules by means of computer simulations. 

Another device that yields results of the same kind as STM is atomic force microscopy (AFM) (Binning, 1986). This avoids dependence on an electron stream (which cannot be obtained from insulators)58 and relies on the actual interatomic forces between a microtip and nearby surface atoms. The forces experienced at a given point by the tip are sensed by a cantilever spring. The movements of this are slight, but they can be measured by means of interf erometry and in this way the movement of the tip can be quantified. The sensitivity of the atomic force microscope is less than that of STM, but its action is independent of the electrical conductivity of the surface and it is therefore to be preferred over STM, particularly for studies in bioelectrochemistiy. 

Binning, G., Quate, C.F., and Gerber, C.H. 1986. Atomic force microscopy. Phys. Rev. Lett. 56,... 

The most important of these techniques is scanning tunnelling microscopy (STM), the invention of Binning and Rohrer45, for which they won the Nobel Prize in Physics in 1986, followed by atomic force microscopy (AFM)47, and which are described in this section, indicating their application to the study of electrode processes. 

The development of local probe techniques such as Scanning Tunneling Microscopy (STM) or Atomic Force Microscopy (AFM) and related methods during the past fifteen years (Nobel price for physics 1986 to H. Rohrer and G. Binning) has opened a new window to locally study of interface phenomena on solid state surfaces (metals, semiconductors, superconductors, polymers, ionic conductors, insulators etc.) at an atomic level. The in-situ application of local probe methods in different systems (UHV, gas, or electrochemical conditions) belongs to modem nanotechnology and has two different aspects. 

Atomic force microscopy (AFM) is a high-resolution 3D imaging technique capable of measuring topographical features to less than 1 nm (Binning et al., 1986). A cantilever with a sharp tip is brought into contact with the surface, in which the force between the tip and the surface results in deflection of the cantilever. The cantilever is rastered over... 

Since the invention of the atomic force microscope (AFM) by Binning et al. (48), which can generate atomic-scale images of materials, this new tool has often been used in combination with electron microscopy to examine the surface and porosity of pillared clays. The principle of this technique is based on scanning the surface of a sample with a very sharp tip, brought within close proximity of the sample, to map the contours of the surface. Hartman et al. (49) demonstrated the ability of the AFM to image molecular-scale features of montmorillonite and illite. Occelli et al. (50,51) conducted a profound characterization of Al-pillared... 

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