Researchers in the US have developed an exquisitely sensitive test, better by a thousand-fold than previous efforts, for detecting trace quantities of cholera and botulinum toxins. These two agents are considered potential agents of a bioterrorist attack. Their test takes just three hours to provide a result.
Until now, the most rapid and sensitive approach to biotoxin detection has involved coupling the polymerase chain reaction (PCR) with antibody specificity for toxins.
To boost the sensitivity of this approach, Jeffrey Mason and colleagues at the Armed Forces Institute of Pathology, Rockville, MD, package about sixty molecules that initiate PCR into a hollow liposome decorated with receptors for the toxin. When present, the toxin binds to 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 toxins – they are detectable even against a background of harmless components in urine and runoff water.
The team reports details of its new test in Nature Biotechnology today.