Work being performed by University of Wisconsin-Madison researchers has the potential to make building atomic-scale machines easier, and also may be the basis for a new class of biological sensors capable of near-instantaneous detection of dangerous biological agents such as anthrax.
The new approach suggests that microbes can serve as forms for complicated nanoscale structures, perhaps obviating, in part, the need for the tedious and time-consuming construction of devices at the smallest scale.

The researchers have developed a system in which living microbes, notably bacteria, are guided, one at a time, down a channel to a pair of electrodes barely a germ's length apart. Slipping between the electrodes, the microbes, in effect, become electrical "junctions," giving researchers the ability to capture, interrogate, and release bacterial cells one by one. Built into a sensor, such a capability would enable real-time detection of dangerous biological agents, including anthrax and other microbial pathogens.

Live bacteria are directed down a narrow channel to a pair of electrodes where they are trapped by mild electric currents. The use of living microbes in such a technology could form the basis for new ways of assembling nanodevices of all kinds. (Photo courtesy of the Hamers Group)

The use of bacterial cells affords a number of potential advantages. For example, capitalizing on the complex topography of the bacterial cell surface and microbial interactions with antibodies, scientists could potentially construct much more complex nanoscale structures through the natural ability of cells to dock with different kinds of molecules. According to the researchers, such a potential would be superior to the painstaking manipulation of individual nanosized components, such as the microscopic wires and tubes that comprise the raw materials of nanotechnology.

In the series of experiments underpinning the new work, the research group showed that it is possible to capture cells along an electrode and then direct them down a narrow channel that acts as a conveyor. Small gaps in the electrical contacts along the conveyor serve as traps that can hold single bacterial cells while their electrical properties are measured. Once the microbial interrogation is completed, the live cell can be released.

Find out more at: http://hamers.chem.wisc.edu