Rapid On-Site Cyanide Assay for Blood and Saliva Samples

DESCRIPTION (provided by applicant): The specific aim of this project is to develop a rapid test for the detection of cyanide in blood and saliva. Poisoning due to cyanide can occur vary rapidly in less than a few minutes, but current tests require at least 2 -3 hours for results to be reported. In rural communities, blood tests for cyanide are sent out for analysis and often several days pass before levels are reported. The current method is a head-space GC technique that uses a strong acid to liberate hydrogen cyanide from cyanomethemoglobin. This results in the administration of antidotal therapy without conformation of poisoning. The antidote, intravenous sodium nitrite, can in itself cause severe poisoning due to hypotension and complications can be exacerbated by anemia. Our technology centers on the strong affinity of cyanide for gold nanoparticles. We have demonstrated that gold nanoparticles can bind free cyanide in aqueous solutions at levels of less than 10 ppb. Most of our prior work has been with aqueous cyanide and gold nanoparticle suspensions, however, some work with HCN detection has been performed with gold nanoparticle impregnated test strips. For this project, we will examine a test for cyanide in blood or saliva using a test strip and a releasing agent to create free cyanide from a biological sample. An example of a potential releasing agent is a strong such as sulfuric acid. Gas permeable membrane technology will also be tested to prevent mixing of releasing agents with the gold nanoparticles. In addition to the chemistry of gold nanoparticles and release of cyanide from cyanomethemoglobin we will show the feasibility of a low cost spectroscopic measurement system. We will eliminate the large and costly portion of Raman spectrometers that is associated with dispersion of the spectrum and replace it with a very small inexpensive filter system. This new system will be designed for handheld use by first response personnel for on-site analysis. The long-term objective of this project will be to provide emergency personnel with small handheld device to measure concentrations of cyanide in blood or saliva. We are working with a local fire department to ensure that the design and specifications match the needs of first response personnel.