Electrodes have been used to trap, interrogate and release individual bacteria in a bio-electronic circuit that could be used to construct nanoscale machines.
"One of the great challenges of nanotechnology remains the assembly of nanoscale objects into more complex systems," says Robert Hamers of the University of Wisconsin-Madison . "We think that bacteria and other small biological systems can be used as templates for fabricating even more complex systems."
To this end, Hamers and colleagues have developed a system in which bacteria are guided down to a pair of electrodes between which they can be captured. A narrow channel acts as a conveyor while small gaps in the electrical contact along the conveyor trap bacterial cells and allow their electrical properties to be measured. The cells can then be released.
Such a system could be used to detect dangerous biological agents such as anthrax. Combined with other technologies, it could also be used to construct nanoscale structures.
"The results here are significant because while there has been much attention paid to the ability to manipulate nanoscale objects such as nanotubes and nanowires across electrical contacts, for many applications the use of bacterial cells affords a number of potential advantages," says Hamers.
For example, researchers could exploit the ability of bacteria to dock with other molecules to form what Hamers calls "nature's nanowires," which can be easily grown and manipulated.
Bacteria could also be engineered to have different surface molecules. It may be possible, for example, to attach gold particles, making bacteria more like nanoscale gold wires.