Assembly from molecular-sized components is a promising approach for the construction of nanoelectromechanical systems (NEMS). The SFM (Scanning Force Microscope) can be used as a manipulation tool to position nanoparticles and nanostructures without the restrictions imposed by the physics of self-assembly [1-3]. Experimental results are presented that show how rigid nanoscale 2-D structures can be formed of individual gold nanoparticles by using bi-functional organic molecules (e.g. dithiols) in combination with dynamic mode SFM manipulation. These structures can be precisely translated by mechanical pushing across the surface or rotated about a specific axis and assembled to form more complicated structures .
Combining SFM manipulation with other nanometer-size surface modification techniques offers new and powerful approaches to nanostructuring. As an example, SFM nanomanipulation and self-assembly of organosiloxanes are discussed. Structures built by SFM nanomanipulation can be immobilized on a surface by deposition of a monolayer film of octadectylsiloxane. 3-D structures can be constructed by placing a new set of nanoparticles on top of the original structures.
Nanostructure assembly in biochemical and medical areas requires that most experiments be performed in a liquid environment. Results of nanomanipulation with an SFM in liquid environments are presented. The underlying mechanics of the manipulation process is found to be the same as in air. Successful manipulation of DNA-modified Au nanoparticles is described as a first example of nanomanipulation of biochemical objects in a liquid.
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Aristides A.G. Requicha
Laboratory for Molecular Robotics
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