Chemical nerve agents also bind to and disrupt other enzymes, including one called butyrylcholnesterase. "Researchers at the laboratory have demonstrated that rat saliva contains a nearly pure population of this enzyme," said Campbell. "This data strongly suggests that it's possible to develop a portable device to yield immediate results from a small amount of saliva. Such a device might save lives in the event of a military or terrorist attack."
Real-time diagnosis is the key, as some treatments for nerve gas poisoning are effective, if initiated in time. Typically, however, testing for chemical exposure requires drawing blood or collecting urine samples, which must then be sent to a laboratory. Results may be days or weeks away.
"If expanded to identify chemical warfare agents, saliva analysis would not only identify those who need medical treatment, but might also offer up forensic evidence against the attackers," said Timchalk. "It might be possible to detect trace levels of the chemical agents in the saliva of a terrorist who handled the poisons before releasing them."
The saliva monitoring technology under development at PNNL is being designed to provide immediate results and be simple enough to be operated in the field by technicians with little training.
"We have demonstrated that a biosensor linked to a hand-held electrochemical detector can identify the organophosphates in solution with a high degree of sensitivity," said Yuehe Lin, a Battelle analytical chemist at PNNL. "The biosensor consists of electrodes coated with carbon nanotubes. The carbon nantotubes hold the enzymes, which are targeted to the organophosphate chemicals, and electricity is applied. If organophophates are present, there is a decrease in the electrical current that can be correlated to the amount of che
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Contact: Susan Bauer
susan.bauer@pnl.gov
509-375-3688
DOE/Pacific Northwest National Laboratory
22-Oct-2003