A Double-Site Chemodosimeter for Selective Fluorescence Detection of a Nerve Agent Mimic

A novel two-site chemodosimeter (SWJT-4) based on fluorescein skeleton to detect diethyl chlorophosphate (DCP) was designed and synthesized. It is a turn-on fluorescent probe for DCP with good selectivity and obvious color change in aqueous solution. Interestingly, the two oxime groups of SWJT-4 as dual response sites initiated different reactions with DCP to form a cyano group and an isoxazole ring, respectively. The corresponding mechanism was confirmed by 1H NMR, MS and DFT calculation. Moreover, SWJT-4 could be used as a fluorescent test paper to detect DCP vapor.

A Complementary Silicon Quantum Dot-Enzyme Platform for Selective Detection of Nitroaromatics Compounds

To address the issue of poor selectivity in nanotechnology-driven, portable nitroaromatics sensors, we have coupled a ratiometric photoluminescence sensor based on silicon quantum dots and fluorescent proteins with a colorimetric enzyme-based sensor. Together, the sensors allow differentiation of nitroaromatic compounds – specifically, distinguishing acetylcholinergic nerve agents from the explosive compounds explored herein. The combined system can detect 2,4,6-trinitrotoluene, 2,4-dinitrotoluene and 4-nitrophenol with micromolar detection limits and affords subsequent differentiation from the nitro-containing nerve agent paraoxon. This demonstrates the advantage of merging elements of materials chemistry and biochemistry to devise customized sensors which can accurately identify hazardous chemical species.

A Complementary Silicon Quantum Dot-Enzyme Platform for Selective Detection of Nitroaromatics Compounds

To address the issue of poor selectivity in nanotechnology-driven, portable nitroaromatics sensors, we have coupled a ratiometric fluorescence sensor based on silicon quantum dots and fluorescent proteins with a colorimetric, enzyme-based sensor. Together, the sensors allow differentiation of nitroaromatic compounds – specifically, distinguishing acetylcholinergic nerve agents from the explosive compounds explored herein. The combined system can detect 2,4,6-trinitrotoluene, 2,4- dinitrotoluene and 4-nitrophenol with micromolar detection limits and affords subsequent differentiation from the nitro-containing nerve agent paraoxon. This demonstrates the advantage of merging elements of materials chemistry and biochemistry to devise customized sensors which can accurately identify hazardous chemical species.

A Rhodamine-Based Probe for Detection of Nerve Agents Simulants

In this paper, a rhodamine-based fluorescent and chromogenic probe, N-(Rhodamine B)-lactam-2-aminobenzyl alcohol (RB-AB), was designed to detect nerve agent simulants. We firstly synthesized RB-AB probe by using rhodamine B and 2-aminobenzyl alcohol as main materials. Secondly, the RB-AB probe was applied to evaluate its ability to detect two nerve agent simulants, diethyl chloride phosphate (DCP) and methyl ethyl chloride phosphate (MECP). It was assumed that RB-AB could react with the nerve agent simulants through the benzyl alcohol group and then undergoes structural changes. As a result, the RB-AB detection solution shows fluorescent and color changes during detecting process. The maximum intensity of fluorescence emission increases with the addition of DCP or MECP in a dose-dependent manner. The LOD (limit of detection) of the probe is about 20 ppm for DCP. Moreover, a significant pink color change can be observed in the RB-AB system within a few seconds when detecting DCP or MECP. In conclusion, a rhodamine-based molecule as a fluorescent and chromogenic probe was developed for detecting nerve agent simulants. The RB-AB probe solutions can give rapid and off-on type optical changes including color and fluorescence when reacting with DCP or MECP. We anticipate that RB-AB probe can be used as a helpful tool for visual and fluorescent detection of nerve agents when meeting with terrorist attacks involving with these agents so that effective measures could be promptly taken to cope with the crises.

A Systematic Review on Nerve Chemical Warfare Agents

The recent poisoning of Russian opposition figure and critic Alexei Navalny on August 20th , 2020 with a Soviet-era Novichok nerve agent reminded the world of the use of chemical agents, especially nerve agents to eliminate individual targets or for mass destruction. Nerve agents are a class of organophosphorus compounds. Soman, Sarin, Tabun, Cyclosarin, VX are a few examples of nerve agents. Nerve agents affect a person by disrupting the mechanism by which nerve signals are passed in the body. They inhibit the action of acetylcholinesterase enzyme which is responsible for the breakdown of acetylcholine neurotransmitters leading to accumulation of acetylcholine in the body. Nerve agents have a range of chemical effects on the eye, gastro-intestinal (GI) tract, Central nervous system (CNS), Respiratory system, Cardiovascular system and Neurological system. The management of nerve agent poisoning is done by administering Atropine or Pralidoxime chloride or also by administering anticonvulsants like Benzodiazepines or Diazepam. This review presents all such detailed information on this class of chemical Warfare agents. Keywords: Chemical Warfare Weapon, Nerve Agents, Acetylcholinesterase, Toxicity, Instrumentation