February 16, 2003

“I envision a hand-held water toxicity biosensor in the pocket of every army medic,” says Professor Shimshon Belkin, head of Hebrew University’s Environmental Science division. A team from the Hebrew University of Jerusalem has created a fast and ingenious way to determine whether water has become contaminated by toxic poisons. Their approach has far-reaching implications for defending against bio-terrorism.

The research not only has far-reaching ramifications for anti-bioterror efforts, but can also be extended to the environment, medical technologies, pharmaceuticals and industry. The story about the research appears in the current issue of the Hebrew University magazine Scopus.

Funded by the U.S. Department of Defense, and led by Professor Shimshon Belkin, head of Hebrew University’s Environmental Science division, the research has developed a process for genetically empowering bacteria to light up if they detect toxins.

Two pieces of DNA, a promoter, which acts as an on/off switch for its neighboring gene and a gene for a fluorescent protein are joined and inserted into the bacteria. When the promoter senses danger the normally inactive gene is turned on and the bacteria becomes fluorescent.

Current methods for testing for toxins in water seem almost archaic – as well as expensive and time consuming. Fish are placed in samples of different concentration of suspect water. After a few days, the number of dead fish is counted. Not only is this method cumbersome, but it also means a lengthy wait.

“Bacteria,” Belkin told Scopus, “have many advantages over fish as testing agents. They can be produces en masse and cheaply, with test results available within minutes or hours. Instead of counting dead fish, luminescence is measured.”

Belkin and his research group are now attempting to further refine such tests. “We want to find an approach that triggers a warning before the test organism even feels ‘unwell’, as soon as it senses minute traces of the undesirable chemicals.”

Belkin heads a multidisciplinary research group funded by the U.S. Department of Defense that comprises teams from the Hebrew University, the Medical Corps of the Israel Defense Forces, the National Public Health Laboratories of the Ministry of Health and Tel Aviv University.

The project could not have been timelier, says Belkin whose research team at the Division of Environmental Science comprises colleagues Dr. Rachel Rosen and Dr. Rami Pedahzur, and graduate student Itay Benovich.

“September 11, 2001 found us in Washington. On September 10, we had presented our project at a DoD installation. They had already decided to fund the project, but thought it mainly relevant to Israel. The next day everything changed,” Belkin said.

At the end of the first year, Belkin’s team has successfully tested both bacterial and yeast cells on a silicon chip and they are continuing their joint efforts to develop a system that not only can tell if the water is toxic, but also pinpoint the level of toxicity and the types of toxins. For this level of analysis, human cells may have to be used.

“I envision a hand-held water toxicity biosensor in the pocket of every army medic,” Belkin says. “The biosensors would be able to detect as many chemicals as possible, with dose-dependent fluorescence – the brighter the light, the higher the toxicity – and different colors lighting up in correlation with different toxins.”

“It’s easy to design a system that tells you that the water may be unsafe. It’s much more complicated to design a system that tells you the water is one hundred percent safe – but that is a challenge we are determined to meet.”

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Jason Harris

Jason Harris

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