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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. [ABSTRACT FROM AUTHOR]

Numerous nanoscale devices and materials have been fabricated in recent years using a variety of biological scaffolds. However, the interfacing of these devices and materials into existing circuits and ordered arrays has proved problematic. Here, we describe a simple solution to this problem using self-assembly of the peptide coiled-coil heterodimer ACID:BASE to immobilize M13 bacteriophage particles to specific locations on a patterned gold surface. Surface plasmon resonance demonstrated that free ACID peptides will assemble onto a surface derivatized with BASE. We then displayed the ACID peptide on the pIX coat protein of M13 and showed that these phage particles permit formation of the coiled-coil resulting in specific surface attachment. The ACID:immobilized BASE affinities appear to be similar for free peptide and phage-displayed ACID. Finally, we fabricated two gold electrodes, separated by a 200 nm gap, coated one of them with BASE and showed that this allows localization of the M13:ACID onto the functionalized electrode.

We discuss the fabrication of closely spaced nanoscale embedded co-planar electrodes with concealed contact wires, using a GaAs-based flip-chip technology. The co-planarity of the electrodes with the substrate and the low roughness of the exposed surface are achieved by templating the deposition of both the dielectric and electrode metal onto a smooth GaAs substrate. The resulting electrodes, with sizes of around 300 nm and separations as low as 25 nm, have RMS roughnesses of less than 0.2 nm and a co-planarity of around 1 nm.

We demonstrate a new process for fabricating embedded co-planar electrodes which combines top-down with bottom-up approaches to nanofabrication. The co-planarity of the electrodes with the substrate surface is achieved by deposition of a dielectric filling layer around a set of lithographically defined metallic electrodes. In order to prevent adhesion of the dielectric to the pre-defined electrodes, an adhesion inhibiting layer, based on a self-assembled monolayer, is formed specifically on the electrode surface prior to deposition of the dielectric. For monolayers with an acid functional group, this adhesion inhibitor yields almost complete non-adhesion of the dielectric filling layer.