The discovery could not only transform food safety, but also make the building of atomic-scale machines far easier. They suggest that microbes could serve as forms for complicated nanoscale structures, perhaps removing, in part, the need for the tedious and time-consuming construction of devices at the smallest scale.
The scientists from the University of Wisconsin-Madison hope that the project could form the basis for a new class of biological sensors capable of near-instantaneous detection of dangerous biological agents.
Nanotechnology involves the study and use of materials at an extremely small scale - at sizes of millionths of a millimetre - and exploit the fact that some materials have different properties at this ultra small scale from those at a larger scale. One nanometer is the same as one millionth of a millimetre.
"One of the great challenges of nanotechnology remains the assembly of nanoscale objects into more complex systems," said Robert Hamers, a UW-Madison professor of chemistry and the senior author of the new reports. "We think that bacteria and other small biological systems can be used as templates for fabricating even more complex systems."
Toward that end, Hamers and his UW-Madison colleagues Joseph Beck, Lu Shang and Matthew Marcus, 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 and microbial pathogens.
"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," said Hamers.
For example, capitalising 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. Such a potential, Hamers argues, 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.
"We spend a lot of time making tiny little nanowires and things of that sort, and then we try to direct them in place, but it is very hard," said Hamers. "However, bacteria and other biological systems can be thought of as nature's nanowires that can be easily grown and manipulated."
The discovery furthers the belief that nanotechnology has vast potential in the application of food production and safety. Researchers in the UK for example were recently awarded a £1.4 million government grant to develop a new generation of micro Rheometers to help characterise and develop liquid based products.
And scientists from the Foundation for Scientific and Industrial Research at the Norwegian Institute of Technology (SINTEF) are looking at whether the film could also provide barrier protection and prevent gases such as oxygen and ethylene from deteriorating food.
The work by Hamers' group was funded by the National Science Foundation in the US. The Wisconsin Alumni Research Foundation, a private, non-profit organisation that manages UW-Madison intellectual property, has applied for patents for the technology.
The paper on this research was presented last week at the San Diego Convention Centre, during a symposium titled "Bioanalytical Techniques for Detection of Bacteria, Toxins and Proteins." The work is also scheduled to appear in the April issue of the journal Nano Letters.