Real-time Detection and Identification of Chemical, Biological, and Explosive (CBE) Agents with Low False Alarm Rates

There is a need for technologies that protect the health and welfare of the American people in a terrorist emergency by detecting acts of biological contamination. Of the chemical, biological, and explosive (CBE) agents, anthrax, smallpox, plague, ricin, botulinum toxin, toxic commercial pesticides, and chemical warfare agents present the most threats. Although there are a variety of techniques to detect these threats, each has some deficiencies.  Raman spectra are very weak; surface-enhanced Raman scattering (SERS) has a large signal response (15 orders of magnitude larger than Raman) and generally requires a metallic surface, limiting its utility in the field; and active laser systems are not portable and thus are of limited use for quick response. To overcome these deficiencies, a Voxtel team has developed a series of CBE taggants composed of metal oxide and semiconductor nanocrystal (NC) quantum dots, which are coupled to custom-designed bio(chemical)-functionalized ligand tethers, that are sensitive to a series of biological, chemical, and explosive agents. CBE-conjugated ligands attach a quenching agent to a nanocrystal emitter, rendering it dark in the absence of a CBE agent. In the presence of a CBE agent, the bioconjugated ligand releases the quenching compound, and a unique optical signature is released that is easily detectable by the eye at short ranges or by LIDAR at longer ranges. In the proposed program, the sensitivity of the CBE taggant to CBE agents will be demonstrated, and the specificity and false alarm rate (FAR) will be characterized. In the first tests, the CBE taggant will be distributed via an aerosol dispersant over a contaminated area, and the detection characterized. Next, field demonstrations will be conducted to demonstrate the ability of these CBE taggants to detect the CBE agent at 2.5 km or more. An innovation with these capabilities has significant benefits and commercial applicability. There is an urgent need to detect the presence of CBE hazards; in particular, water and food supplies need to be protected. Additionally, more benign threats, such as salmonella, need to be detected. Leveraging its work in taggants, Voxtel proposes to first develop a small-sized CBE colorimetric technology, that is used as a spray or coating, employing a biotaggant that does not undergo color change when an agent is present. Agent disclosure spray visually indicates contaminated areas requiring treatment; this will minimize the time, labor, and material required because only the indicated areas will require decontamination.