Three in one fluorescent sensing and imaging of chemical warfare agents.

Chemical warfare agents (CWAs) pose severe global threats due to their historical role in mass casualties and ongoing misuse, particularly blister, nerve, and blood agents. To address the urgent need for field-deployable detection tools, we develop TrioAlert, which, to the best of our knowledge, is the first fluorescent sensor capable of simultaneously detecting the blister agent sulfur mustard, the G-type nerve agent sarin, and the blood agent cyanide. The sensor employs an imidazole moiety for the recognition of sulfur mustard and sarin, while cyanide is detected through a reaction at the 4-position of the coumarin fluorophore. TrioAlert demonstrates a rapid response (within 90 s), high sensitivity (limits of detection: 58.5 nM for sulfur mustard, 46.2 nM for sarin, and 53.4 nM for cyanide), and distinct fluorescence and color changes. The detection performance of TrioAlert for the three chemical warfare agents remains stable in natural environmental matrices and across various temperatures. Furthermore, TrioAlert-loaded test strips enable smartphone-based qualitative and quantitative on-site analysis, with visual detection limits of 0.05 ppm for sulfur mustard, 0.01 ppm for sarin, and 5 ppm for cyanide. The sensor also enables the visualization of all three CWAs in live cells and mouse models. Notably, in vivo fluorescence changes precede pathological damage, with distinct fluorescence triggered at sub-pathological doses. This provides an early visual indication for trace CWA exposure. Furthermore, these fluorescence changes correlate with subsequent alterations in pathological biomarkers (P < 0.01), confirming the sensor's potential for clinical diagnosis. Our study demonstrates the on-site rapid quantitative detection of high-risk chemical warfare agents, thereby advancing the capability to prevent chemical threats and safeguard public health and security.