New Decontamination System Kills Anthrax Rapidly Without Lingering Effects

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ScienceDaily (Feb. 4, 2008) — In October 2001, letters containing anthrax spores were mailed to several news media offices and two U.S. senators, killing five people and infecting 17 others. Clearing the Senate office building of the spores with chlorine dioxide gas cost $27 million, according to the Government Accountability Office. Cleaning the Brentwood postal facility outside Washington cost $130 million and took 26 months.




Researchers at the Georgia Tech Research Institute (GTRI) in collaboration with Austin-based Stellar Micro Devices, Inc. (SMD) have developed prototypes of a rapid, non-disruptive and less expensive method that could be used to decontaminate bioterrorism hazards in the future.

Using flat panel modules that produce X-rays and ultraviolet-C (UV-C) light simultaneously, the researchers can kill anthrax spores in two to three hours without any lingering effects. The system also has the ability to kill anthrax spores hidden in places like computer keyboards without causing damage.

"This is certainly an improvement over previous techniques," said Brent Wagner, GTRI principal research scientist and director of its Phosphor Technology Center of Excellence (PTCOE). "The UV-C attacks spores on surfaces and the X-rays penetrate through materials and kill spores in cracks and crevices."

X-ray irradiation is used commercially to sterilize medical products and food by disrupting the ability of a microorganism to reproduce. UV-C also prevents replication, but both types of radiation can penetrate the outer structure of an anthrax spore to destroy the bacteria inside.

The current decontamination standard -- chlorine dioxide gas -- kills microorganisms by disrupting transport of nutrients across the cell wall, but cannot reach hidden spores. Hard surfaces must be cleaned independently with harsh liquid chlorine dioxide. In addition, people cannot re-enter a room fumigated with chlorine dioxide until the gas is neutralized with sodium bisulfite vapor and vented from the building.

The new decontamination system resembles a coat rack with radiation modules arranged on rings at various heights that face outward to broadcast radiation throughout a room. Since the X-rays and UV-C are lethal at the flux densities used, the system operates unattended and is turned on outside the affected space.

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http://www.sciencedaily.com/releases/2008/01/080129125415.htm