Development of a Field-Deployable Device to Rapidly Measure Blood Cyanide Levels

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PROJECT SUMMARY The objective of this proposal is to complete the development and verify the performance of a field-deployable, fully integrated sensor for the rapid and early diagnosis of cyanide poisoning in whole blood. Cyanide is an extremely potent and rapid acting poison. It can be inhaled or absorbed across the skin as cyanide gas or ingested as cyanide salt, and has multiple mechanisms of toxicity. Smoke inhalation containing cyanide is one of the main causes of cyanide related casualties in residential fires. Antidotes to cyanide poisoning are currently available, although at a high price. While new and more effective therapeutic agents are in development, there is no rapid diagnostic test to support emergency personnel and first responders who have a need to measure cyanide levels in whole blood quickly in order to safely and effectively treat exposed individuals. Our test is intended to fill that niche. We propose to complete the development of our prototype sensor into a fully functional and integrated test device and to verify its performance. We have established and proven the chemistry and functionality of the chemical sensor and we have integrated the sensor into a microfluidic cartridge that collects a measured amount of blood from a finger-stick, contains all the reagents and buffers, and houses the cyanide sensor. In our prototype microfluidic cartridge a fixed amount of a whole blood sample is collected, the red blood cells are lysed, then passed through the sensor, followed by a manually actuated wash step. In this phase we will first complete the integration of the cyanide sensor and lysis/wash buffer reagents into the microfluidic cartridge after making improvements to and optimizing the cartridge to resolve remaining performance challenges. Testing to qualify and verify the disposable will be done initially with our prototype benchtop reader. In parallel, our main efforts will focus on the hand-held reader development. After a concept stage, alpha versions of the field-deployable instrument will be developed and tested with the cartridge to confirm functionality and to identify areas for improvement. In addition, alpha readers will be evaluated in a usability study with intended users, firefighters and EMT’s, to evaluate their performance and obtain feedback to improve the design and functionality of the system. Hardware and software development of our reader are then scheduled to progress to a pre-production stage and undergo extensive complete system testing prior to the end of this project. The preproduction system performance, disposable and instrument, will be thoroughly evaluated with samples from cyanide exposed rabbits and pigs, as animal models, and spiked human blood. Verification studies for this Phase will include the confirmation of sensitivity/specificity (≥95%), limit of detection (≤20 µM), dynamic range (20-150 µM), accuracy/reproducibility (≤20% variability), assay time (≤5 minutes), and other studies that are typically required for FDA approval. Clinical studies with production equivalent tests will be initiated upon completion of this Phase.