A palladium (Pd) nanowire-based hydrogen (H2) sensor has been fabricated with a novel viral-templated assembly route. A filamentous M13 bacteriophage was used as the viral-template for assembly of Pd nanowires at ambient conditions.
Scanning electron microscopy determined Pd nanowire distribution and morphology with the devices. The phage
template concentration controlled the number of physical and electrical nanowire connections across the device. A
greater phage concentration resulted in a higher connection density and thicker Pd deposition. A lower phage
concentration generated devices which formed chain-like nanowires of Pd nanocrystals, whereas a higher phage
concentration formed devices with a continuous mesh-like structure. The lower concentration devices showed 51-78%
instantaneous response to 2000 ppm H2 and response time less than 30 s.
Preliminary studies toward the assembly of a gold-polypyrrole (PPy) peapod-like chemiresistive ammonia (NH3) gas
sensors are presented. The proposed synthesis process will use electropolymerization to embed gold nanoparticles in
polypyrrole nanowires. Viral-templating of gold nanoparticles and PPy electrodeposition via cyclic voltammetry are the
focus of this investigation. A gold-binding M13 bacteriophage was used as a bio-template to assemble continuous
chains of gold nanoparticles on interdigitated Pt working electrodes. The dimensions of the resulting nanowire-like
structures were examined and the electrical resistance measured. PPy films were electropolymerized using an
interdigitated planar, Pt electrode integrated counter and reference electrode. Morphological characterization of the
polymer films was completed.