ITHACA, N.Y. -- Detecting potentially deadly bacteria in food, the water supply or on the battlefield before it does damage has never been reliable or fast enough to prevent death, illness or economic loss. As just one example, last year a Columbus, Neb., beef-processing plant was forced to recall 25 million pounds of hamburger when less than a speck of bacteria was detected.
But now Cornell University researchers have merged the fields of nanofabrication and biology to produce a simple but effective means to detect harmful bacteria. New biosensors can detect minute quantities of bacteria, from the slaughterhouse to the restaurant, and send up a red flag when there's a problem.
The biosensors, developed by Harold Craighead, professor of applied and engineering physics, in collaboration with Carl Batt, professor of food science, are simple in concept and arose from technology that is the mainstay of the microelectronics industry. The sensors capture bacteria in a regular, repeating pattern and, similar to the UPC bar code used in a supermarket, can be read using a laser beam.
"It's like a printing press," says Batt. "By stamping antibodies on the surface, the bacteria will be bound to the sensor, and they then form a pattern that can be read with a laser. It is a very fast, direct method for detecting bacteria."
The research is reported in the latest issue of Analytical Chemistry (March 15). The senior author on the paper with Batt and Craighead is Pamela St. John, a former postdoctoral fellow at Cornell. The other authors are Robert Davis, a Cornell postdoctoral fellow, John Czajka, a recent graduate student in food science, and Nathan Cady, an undergraduate in biology.
Using Cornell's nanofabrication facility, the researchers made small-scale rubber stamps imprinted with diffraction gratings, which are the patterns of the lines of bacteria-seeking antibodies. In this case the Cornel
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Contact: David Brand
deb27@cornell.edu
607-255-3651
Cornell University News Service
7-Apr-1998