Scientists have developed a test that is at least a thousand times more sensitive than the best current approaches for detecting in the field trace quantities of cholera and botulinum toxins, two possible agents for contamination of food or drinking water during a bioterror attack. The method, described in the May 2006 issue of Nature Biotechnology, provides results in just 3 hours.
Until now, the most rapid and sensitive approach to biotoxin detection has involved coupling a technique called PCR, perhaps best known for its capacity for massive amplification of trace amounts of DNA found at crime scenes, with the exquisite specificity conferred by antibodies capable of specifically fishing biotoxins out from complex samples such as milk.
To boost the sensitivity of this approach, Jeffrey Mason and colleagues package about sixty molecules that initiate PCR into a hollow oil droplet (called a liposome) decorated with receptors for the toxin. When present, the toxin binds the receptors, and when the liposome is subsequently broken open, the released PCR-initiating molecules amplify the signal and enable detection of vanishingly small amounts of biotoxins - even against a background of harmless components in urine and runoff water from land housing livestock.
Not only is the test exquisitely sensitive, but it also avoids the use of animals, unlike the US Centers for Disease Control botulinum bioassay.
Jeffrey T. Mason (Armed Forces Institute of Pathology, Rockville, MD, USA)
Additional contact for comment on this paper:
Timothy J. O'Leary (Veterans Health Administration, Washington, DC, USA)
Abstract available online.
(C) Nature Biotechnology press release.
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