Proteins and peptides as biological nanowires: towards biosensing devices

The current landscape of nanotechnology is such that attention is being given to those materials that self-assemble, as a mode of "bottom-up" fabrication of nanomaterials. The field of nanotubes and nanowires has long been dominated by carbon nanotubes and inorganic materials. However in more recent years, the search for materials with desirable properties, such as self-assembly, has unsurprisingly led to the biological world, where functional nanoscale biomolecular assemblies are in abundance.Potential has been seen for a number of these assemblies to be translated into functional nanomaterials. The early days of bionanotechnology saw a lot of attention given to DNA molecules as nanowires, and proteins and peptides have now also been seen to have promise in this area. With most of the biological structures investigated having low conductivity in the native state, the use of biomolecules as templates for the formation of metallic and semiconductor nanowires has been the direction taken.This chapter will discuss the use of various biomolecules and biomolecular assemblies as nanowires, with a particular emphasis on proteins, beginning with an introduction into the field of nanotubes and nanowires. Many applications are now recognized for nanowires, but for brevity, this chapter will focus solely on their use as biosensors, using glucose sensors as a case study.