Bacteria of the Future Detect Bio-Terror Agents, Call for Help

MADISON, Wisconsin, March 21, 2005 (ENS) - A live bacterial cell is directed down a narrow channel to a pair of electrodes where it is trapped by mild electric currents. The cell is held while its electrical properties are measured. Once the microbial interrogation is completed, the living cell is released.

The team of scientists at the University of Wisconsin-Madison that created this system says the chemicals on the surface of bacterial cells could be wired in a way that would be the basis for a real-time biological sensor.

This kind of sensor could be placed in airports, stadiums, railway stations, skyscrapers, mailrooms and other public areas to sniff for dangerous biological agents that might be used to touch off a bioterror event.

Robert Hamers, a UW-Madison professor of chemistry and the senior author of the new report, believes the new work could be the basis for bringing nanotechnology and biology together in novel ways.

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Robert Hamers (right) was presented with the 2005 Arthur Adamson Medal by Bill Carroll, president of the American Chemical Society. (Photo courtesy Hamers Group)
For his work at the intersection of microelectronics, nanotechnology, and biotechnology, Hamers was presented with the 2005 Arthur Adamson Medal by Bill Carroll, president of the American Chemical Society, March 15, 2005 at the society's meeting in San Diego, California.

Hamers says the work of his group is important because it has the potential to make building the atomic scale machines of the nanotechnologist easier.

"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," says Hamers. "However, bacteria and other biological systems can be thought of as nature's nanowires that can be easily grown and manipulated."

This work is expected to provide the basis for a new class of biological sensors capable of nearly instantaneous detection of dangerous biological agents such as anthrax.

The biological sensing device could be constructed, says co-author Joseph Beck, utilizing the natural features bacteria and other microbes use to sense their environments.

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Post-doctoral researcher Joe Beck is part of the Hamers Group. (Photo courtesy UW)
The wired bacterial cells, coupled with modern microelectronics, would have the ability not only to detect dangerous agents such as anthrax spores, but they then could sound the alarm and call for help.

"You could even engineer bacteria to have different surface molecules that you could capitalize on," says Beck.

For instance, it may be possible, the Wisconsin scientists say, to attach microscopic gold particles to the shell of the bacterium, making it more like a nanoscale gold wire.

"One of the great challenges of nanotechnology remains the assembly of nanoscale objects into more complex systems," says Hamers. "We think that bacteria and other small biological systems can be used as templates for fabricating even more complex systems."

Hamers heads an interdisciplinary group of scientists at UW-Madison that is exploring the interfaces between inorganic materials such as silicon, diamond, nanotubes, nanowires, and living organic biological molecules.

Hamers' group of 17 graduate students and post-doctoral associates is joined this year by eighth grade student Adam Schneider from Eagle School in Fitchburg, Wisconsin. He is doing research with Hamers group grad student Sarah Baker on carbon nanofibers as part of the Eagle School's Science Mentor Program.

Much of the group's research lies at the intersection of microelectronics, nanotechnology, and biotechnology. "Just as an architect uses simple materials to build functional complex structures, much of what we do is use the physical and chemical properties of individual molecules to build more complex interface structures with specific types of functionality," Hamers explains.

The group is part of the UW-Madison Nanoscale Science and Engineering Center. http://www.nsec.wisc.edu/. The work by Hamers' group was funded by the National Science Foundation as part of a $13.4 million grant to fund nanoscience at UW-Madison.

The Wisconsin Alumni Research Foundation, a private, nonprofit organization that manages UW-Madison intellectual property, has applied for patents for the technology.

Reported March 17 at the meeting of the American Chemical Society in San Diego, the work is also scheduled to appear in the April issue of the journal "Nano Letters."