The electronics industry has consistently decreased the dimensions of structural components and they are now well into the nanoscale range. Naturally, a significant portion of the chip is composed of interconnects. Besides, the engineering problems associated with short wavelength lithography to achieve smaller components, the performance of increasing number of interconnections has become one of the biggest limiting factors in device performance.[1,2] The power loss, signal degradation, interconnection delays, and other performance limitations related to interconnects should be minimized. The importance of such a task can be seen from the perspective of power dissipation by computation elements. The energy dissipation density in electronic chips approaches that in nuclear reactors. [3,4]

No abstract

A novel method for the synthesis of high‐active‐surface‐area, platinum–tobacco mosaic virus (Pt–TMV) nanotubes is presented. A platinum salt is reduced to its metallic form on the external surface of a rod‐shaped TMV by methanol, which serves as a solvent and reductant simultaneously. It was found that for the same Pt loading the Pt–TMV nanotubes had an electrochemically active surface area between 4 to 8 times larger than similarly sized Pt nanoparticles. A Pt–TMV catalyst displays greater stability in acidic conditions than those based on nanoparticles. When used as a catalyst for methanol oxidation, these Pt nanotubes display a 65% increase in catalytic mass activity compared to that based on Pt nanoparticles.

This work presents nanoscale four-probe measurements on metallic nanowires using independently controlled scanning tunnelling microscope tips. This technique has allowed us to follow the change in resistance with probe separation. Gold, zinc and nickel nanowires were grown by electrodeposition within porous polycarbonate membranes. Their structure and composition were studied by transmission electron microscopy. Four-probe electrical transport measurements were taken using four independently controlled scanning tunnelling microscope tips positioned using a high resolution scanning electron microscope. Multiple I–V measurements were taken at varying tip separations, on each nanowire, and the change in resistance with separation was observed to be in good agreement with predictions based on the nanowire geometry. The resistivity values of the nanowires were found to be close to bulk values.

The rod-shaped plant virus tobacco mosaic virus (TMV) is widely used as a nano-fabrication template, and chimeric peptide expression on its major coat protein has extended its potential applications. Here we describe a simple bacterial expression system for production and rapid purification of recombinant chimeric TMV coat protein carrying C-terminal peptide tags. These proteins do not bind TMV RNA or form disks at pH 7. However, they retain the ability to self-assemble into virus-like arrays at acidic pH. C-terminal peptide tags in such arrays are exposed on the protein surface, allowing interaction with target species. We have utilized a C-terminal His-tag to create virus coat protein-templated nano-rods able to bind gold nanoparticles uniformly. These can be transformed into gold nano-wires by deposition of additional gold atoms from solution, followed by thermal annealing. The resistivity of a typical annealed wire created by this approach is significantly less than values reported for other nano-wires made using different bio-templates. This expression construct is therefore a useful additional tool for the creation of chimeric TMV-like nano-rods for bio-templating.

We report the binding of nanoparticles (NPs) to wild type (unmodified) tobacco mosaic virus (TMV). The viruses are simply mixed with citrate-coated, negatively charged gold and iron oxide nanoparticles (IONPs) in acidic solution. This results in TMV decorated along its whole length by the respective particles. Such a decoration usually requires chemical modification or mutation of TMV (e.g., cysteine residues), but here we simply reduce TMV's natural negative charge by protonation. The particles are protonated to a much smaller extent. This charge-based mechanism does not operate for neutral particles.

The electrical transport and structural properties of tobacco mosaic virus (TMV)-based nanostructures have been studied. Electroless deposition was used to coat the TMV outer surface with a 13 nm thick homogeneous Pt layer. SEM, TEM and electrical characterization of the obtained nanostructures has been performed. Using four independently controlled scanning tunnelling microscope tips we were able to perform four-point probe resistance measurements on linear virus assemblies and demonstrate the continuous nature of the metallic coating. The measured resistivity values of the virial nanowires exceeded the bulk value by 10-100 times; notwithstanding this the coated structure allowed high current densities, of the order of 10(5)-10(8) A cm(-2). The four-probe technique proved to be useful for analysing the electrical properties of bio-inorganic nanowires.

Nanoscale science refers to the study and manipulation of matter at the atomic and molecular scales, including nanometer-sized single objects, while nanotechnology is used for the synthesis, characterization, and for technical applications of structures up to 100 nm size (and more). The broad nature of the fields encompasses disciplines such as solid-state physics, microfabrication, molecular biology, surface science, organic chemistry and also virology. Indeed, viruses and viral particles constitute nanometer-sized ordered architectures, with some of them even able to self-assemble outside cells. They possess remarkable physical, chemical and biological properties, their structure can be tailored by genetic engineering and by chemical means, and their production is commercially viable. As a consequence, viruses are becoming the basis of a new approach to the manufacture of nanoscale materials, made possible only by the development of imaging and manipulation techniques. Such techniques reach the scale of single molecules and nanoparticles. The most important ones are electron microscopy and scanning probe microscopy (both awarded with the Nobel Prize in Physics 1986 for the engineers and scientists who developed the respective instruments). With nanotechnology being based more on experimental than on theoretical investigations, it emerges that physical virology can be seen as an intrinsic part of it.