Ultrasensitive in situ label-free DNA detection using a GaN nanowire-based extended-gate field-effect-transistor sensor.

In this study, we have successfully demonstrated that a GaN nanowire (GaNNW) based extended-gate field-effect-transistor (EGFET) biosensor is capable of specific DNA sequence identification under label-free in situ conditions. Our approach shows excellent integration of the wide bandgap semiconducting nature of GaN, surface-sensitivity of the NW-structure, and high transducing performance of the EGFET-design. The simple sensor-architecture, by direct assembly of as-synthesized GaNNWs with a commercial FET device, can achieve an ultrahigh detection limit below attomolar level concentrations: about 3 orders of magnitude higher in resolution than that of other FET-based DNA-sensors.

Patterned growth of ZnO nanostructures based on the templation of plant cell walls.

A new and general approach based on vapor-phase transport technique using Au-coated plant cell walls has been developed to synthesize patterned ZnO nanostructures. Nanowires, nanodendrites and nanotowers were fabricated by adsorption of different metallic ions on plant cell walls. It is shown that plant cell wall can serve as a well-defined template to grow patterned nanostructures.