Clemson Researchers Create Biosensors To Protect Nation's Food And Water Supplies

An early warning detection system is urgently needed. At Clemson University, researchers are developing a biosensor that will make contaminated food glow in the dark.

A team of chemists, microbiologists and food scientists have devised a way to tether luminescent molecules to food pathogens, such as E.coli, and Salmonella. Using nanotechnology, the researchers are building a new screening method to protect our food supply.

"What's needed is a simple, low cost way to rapidly detect pathogens at the site of contamination, not having to wait for lab results," said food science professor and team leader Paul Dawson. "What we have worked on are particles that are luminescent, providing a way to flash an alarm to hold the food for closer examination."

Chemists used a similar technique to identify worms in pecans. The worms would absorb a chemical that would glow under UV or "black" light. Dawson, along with professors Ya-Ping Sun, Xiuping Jiang, Feng Chen and James C. Acton, have miniaturized the process by applying nanotechnology, the science of building structures at molecular and atomic levels. It is not just the science of the very small, it is a technology, enabling the practical application of that knowledge by scientists who investigate arranging atoms to create innovations that can be seen only with electron microscopes.

Nature does a great job of putting together molecules and other nanoscale components in complex patterns, Dawson said. His team is working on a single molecule process, creating a "protein key" that would "key and lock" with another molecule and creating a bio-alarm, when key and lock fit. Most pathogens and toxins have a unique "lock," and by attaching the matching "key" on the surface of a luminescing nanoparticle, a nanosensor can be created. The sensor signal can be rapidly detected and be a first line of defense in identifying food or water that has been contaminated.

"The nanoparticle can move into crevices in the food source, where a pathogen could be hidden from microscopic view," Dawson said. "The particle's extremely small size increases the odds that the antibody and antigen will link, enabling the sensor to give off a glow. The more connections, the greater the glow."

Derived from the Greek word for midget, "nano" means a billionth part. A nanometer (abbreviated nm), for example, is one billionth of a meter. An atom measures about one-third of a nanometer. The diameter of a human hair is about 200,000 nm.