Virus-based nanoelectronic devices

Bacteriophages are useful templates for the fabrication of electronically useful nanostructures. These phage-based nanostructures can be self-assembled into simple nanoelectronics device using the molecular recognition properties displayed on their surface. The aim of this work was to use such phage-based nanostructures to form a self-assembling molecular transistor. Filamentous bacteriophage M13 and icosahedral bacteriophage MS2 were selected for the fabrication of the gold nanowires and nanoparticle encapsulated capsid respectively. First a ~1 µm long gold nanowire was made by modifying the major coat protein, pVIII to express gold binding peptide on its surface. This phage bound to gold nanoparticles of various sizes. Then a dual functional phage was created by genetically modifying the minor coat protein gene, gIII of this gold binding phage to express biotin binding motif on pIII. Although, this phage bound to florescent tagged biotin, but the binding affinity was not strong enough to bind other biotin functionalized phage and form higher order structures. Physical and electrical characterization of these nanostructures were carried out. The gold nanowire was found to have an electrically insulating coat on their surface which could be burnt off after passing current through it at high voltage sweeps. The MS2 bacteriophage encapsulated gold nanoparticles of various sizes and their encapsulation efficiency was determined. The pores on the surface of the phage were used to modify the encapsulated nanoparticle. AFM tip was moved using a virtual haptic to manipulate such virus-templated nanostructures on silica and mica surfaces in order to fabricate rapid prototypes of nanoelectronic device. Although, much progress was made towards the goal of a self-assembling transistor, the aspects devised within this study need to be combined.