1. Scope of Article and Previous Related Reviews 5346 2. Introduction 5346 2.1. Destruction 5347 2.2. Sensing 5347 2.3. Historical Context 5348 2.3.1. Brief History and Molecular Structure 5348 2.4. Related Compounds and Nomenclature 5348 2.4.1. Phosphorus(V) Parent Compounds and Fundamental Chemistry 5348 2.4.2. Pesticides 5349 2.4.3. Simulants 5349 2.4.4. Decomposition Products 5350 2.5. Toxicology 5351 2.5.1. Acetylcholine Esterase (AChE) Inhibition 5351 2.5.2. Endocannabinoid System Activation 5352 2.6. Critical Needs To Decontaminate and Detect 5353 2.7. Treaties and Conventions 5354 3. Stockpile Destruction 5355 3.1. Agent Storage 5355 3.2. Protection Protocols and Logistics 5355 3.3. Background 5355 3.4. Methods Currently Employed 5355 3.4.1. Incineration 5355 3.4.2. Neutralization by Base Hydrolysis 5356 4. Decomposition Reactions 5357 4.1. Hydrolysis 5357 4.2. Autocatalytic Hydrolysis or Hydrolysis Byproducts 5358 4.3. Use of Peroxide 5359 4.4. Oxidation with Bleach and Related Reagents 5360 4.5. Alkoxide as Nucleophile 5360 4.5.1. Basic Media 5360 4.5.2. Metal-Catalyzed Reactions 5361 4.5.3. Metal-Assisted Reactions 5363 4.5.4. Biotechnological Degradation 5363 4.5.5. Cyclodextrin-Assisted Reactions 5370 4.6. Halogen as the Nucleophile 5370 4.6.1. Use of BrOx 5370 4.6.2. Use of Other Halogens 5371 4.6.3. Use of Group 13 Chelates 5371 4.7. Surface Chemistry 5371 4.7.1. Bare Metals and Solid Nanoparticles 5371 4.7.2. Metal Oxides 5371 4.7.3. Representative Elements 5372 4.7.4. d-Block (Groups 4 10) 5373 4.7.5. Solid Metal Oxides of Group 3 and the Lanthanides 5375 4.7.6. Porous Silicon and Related Systems 5375 4.7.7. Zeolites 5375 4.7.8. Comparative IR Data 5375 4.8. Other Types of Systems 5375 5. Decontamination 5376 5.1. Overview: Ability to React with All Types of Agents, Ease of Application, and Compatibility with Treated Objects 5376 6. Agent Fate and Disposal 5378 6.1. Indoor 5378 6.2. Concrete and Construction Surfaces 5378 6.3. Landfills 5379 7. Sensing and Detection 5379 7.1. Possible Metal Ion Binding Modes in Solution 5379 7.1.1. Early Reports of Phosph(on)ate [R3PdO 3 3 3M nþ] Interactions (R= Alkyl, Alkoxyl) 5380 7.1.2. Coordination Chemistry of Downstream Non-P-Containing Products of Decomposition 5380 7.2. Colorimetric Detection 5381 7.3. Chemiluminescence: Fluorescence and Phosphorescence 5382 7.3.1. Lanthanide-Based Catalysts 5382 7.3.2. Organometallic-Based Sensors 5382 7.3.3. Organic Design 5382 7.3.4. Biologically-Based Luminescence Detection 5382 7.3.5. Polymer and Bead Supports 5382 7.4. Porous Silicon 5383 7.5. Carbon Nanotubes 5383

Destruction and Detection of Chemical Warfare Agents

A review of molecular recognition technologies for detection of biological threat agents.

Nitroaromatic compounds are xenobiotics that have found multiple applications in the synthesis of foams, pharmaceuticals, pesticides, and explosives. These compounds are toxic and recalcitrant and are degraded relatively slowly in the environment by microorganisms. 2,4,6-Trinitrotoluene (TNT) is the most widely used nitroaromatic compound. Certain strains of Pseudomonas and fungi can use TNT as a nitrogen source through the removal of nitrogen as nitrite from TNT under aerobic conditions and the further reduction of the released nitrite to ammonium, which is incorporated into carbon skeletons. Phanerochaete chrysosporium and other fungi mineralize TNT under ligninolytic conditions by converting it into reduced TNT intermediates, which are excreted to the external milieu, where they are substrates for ligninolytic enzymes. Most if not all aerobic microorganisms reduce TNT to the corresponding amino derivatives via the formation of nitroso and hydroxylamine intermediates. Condensation of the latter compounds yields highly recalcitrant azoxytetranitrotoluenes. Anaerobic microorganisms can also degrade TNT through different pathways. One pathway, found in Desulfovibrio and Clostridium, involves reduction of TNT to triaminotoluene; subsequent steps are still not known. Some Clostridium species may reduce TNT to hydroxylaminodinitrotoluenes, which are then further metabolized. Another pathway has been described in Pseudomonas sp. strain JLR11 and involves nitrite release and further reduction to ammonium, with almost 85% of the N-TNT incorporated as organic N in the cells. It was recently reported that in this strain TNT can serve as a final electron acceptor in respiratory chains and that the reduction of TNT is coupled to ATP synthesis. In this review we also discuss a number of biotechnological applications of bacteria and fungi, including slurry reactors, composting, and land farming, to remove TNT from polluted soils. These treatments have been designed to achieve mineralization or reduction of TNT and immobilization of its amino derivatives on humic material. These approaches are highly efficient in removing TNT, and increasing amounts of research into the potential usefulness of phytoremediation, rhizophytoremediation, and transgenic plants with bacterial genes for TNT removal are being done.

/pdf/biological-degradation-of-2-4-6-trinitrotoluene-2fb04se8mb.pdf

Biological Degradation of 2,4,6-Trinitrotoluene

Biosensors incorporate a biological sensing element that converts a change in an immediate environment to signals conducive for processing. Biosensors have been implemented for a number of applications ranging from environmental pollutant detection to defense monitoring. Biosensors have two intriguing characteristics: (1) they have a naturally evolved selectivity to biological or biologically active analytes; and (2) biosensors have the capacity to respond to analytes in a physiologically relevant manner. In this paper, molecular biosensors, based on antibodies, enzymes, ion channels, or nucleic acids, are briefly reviewed. Moreover, cell-based biosensors are reviewed and discussed. Cell-based biosensors have been implemented using microorganisms, particularly for environmental monitoring of pollutants. Biosensors incorporating mammalian cells have a distinct advantage of responding in a manner that can offer insight into the physiological effect of an analyte. Several approaches for transduction of cellular signals are discussed: these approaches include measures of cell metabolism, impedance, intracellular potentials, and extracellular potentials. Among these approaches, networks of excitable cells cultured on microelectrode arrays are uniquely poised to provide rapid, functional classification of an analyte and ultimately constitute a potentially effective cell-based biosensor technology. Three challenges that constitute barriers to increased cell-based biosensor applications are presented: analytical methods, reproducibility, and cell sources. Possible future solutions to these challenges are discussed.

Development and application of cell-based biosensors.

This review deals with cryotropic gelation in polymeric systems, which takes place on moderate freezing, storing in a frozen state and subsequent thawing of solutions or colloidal dispersions containing monomeric or polymeric precursors. The polymer materials formed under these conditions are termed as cryogels. They are macroporous heterophase gels in which polycrystals of the frozen solvent act as porogens during gel formation. The current knowledge about the structure of moderately frozen solutions of low- and high-molecular-mass compounds is considered, the general regularities of the cryotropic gelation processes and their similarity to and differences from gelation at positive temperatures are discussed, the fields of application of cryotropic gelation techniques are described, and examples of using polymeric cryogel-based materials for solving applied problems are given. The bibliography includes 433 references.

https://iopscience.iop.org/article/10.1070/RC2002v071n06ABEH000720/pdf

Cryogels on the basis of natural and synthetic polymers: preparation, properties and application

The development of a new biosensor based on recombinant E. coli for the direct detection of organophosphorus neurotoxins.

2,4,6-Trinitrotoluene (TNT), a toxic nitroaromatic explosive, accumulates in the environment, making necessary the remediation of contaminated areas and unused materials. Although bioremediation has been utilized to detoxify TNT, the metabolic processes involved in the metabolism of TNT have proven to be complex. The three aerobic bacterial strains reported here (Pseudomonas aeruginosa, Bacillus sp., and Staphylococcus sp.) differ in their ability to biotransform TNT and in their growth characteristics in the presence of TNT. In addition, enzymatic activities have been identified that differ in the reduction of nitro groups, cofactor preferences, and the ability to eliminate-NO2 from the ring. The Bacillus sp. has the most diverse bioremediation potential owing to its growth in the presence of TNT, high level of reductive ability, and capability of removing-NO2 from the nitroaromatic ring.

Biotransformation patterns of 2,4,6-trinitrotoluene by aerobic bacteria

Organophosphorus hydrolase (OPH) is a bacterial enzyme that hydrolyzes a variety of organophosphorus (OP) neurotoxins, including many widely used pesticides and chemical warfare agents containing P-O, P-F, P-CN and P-S bonds. It has extremely high efficiency in hydrolysis of many different phosphotriester and phosphothiolester pesticides (P-O bond) such as paraoxon (kcat3800s−1) and coumaphos (kcat = 800s−1) or phosphonate (P-F) neurotoxins such as DFP (kcat = 350s−1) and the chemical warfare agent sarin (kcat = 56s−1). In contrast, the enzyme has much lower catalytic capabilities for phosphonothioate neurotoxins such as acephate (kcat = 2.8 s−1) or the chemical warfare agent VX [O-ethyl S-(2-diisopropyl-aminoethyl) methylphosphonothioate] (kcat = 0.3s−1). This lower specificity for VX and its analogues are reflected by the specificity constants (kcat/Km values) for VX = 0.75 × 103 M−1 s−1 compared to 5.5 × 107M−1 s−1 for paraoxon. Different metal-associated forms of the enzyme demonstrated significantly ...

Enzymatic Hydrolysis of the Chemical Warfare Agent VX and its Neurotoxic Analogues by Organophosphorus Hydrolase

A radically new approach for the discriminative determination of various neurotoxins has been developed. This novel biosensor combines a highly sensitive acetylcholinesterase (AChE) biosensor with immobilized organophosphate hydrolase (OPH). The value of the new concept was demonstrated by the discrimination between carbamate and organophosphorus pesticides. It was shown that the response of traditional AChE-based biosensor to mixed samples containing paraoxon and carbofuran was not simply additive, and the measured concentrations of these pesticides were very different from their real concentrations. This combined OPH/AChE system was able to improve the accuracy of the AChE-based biosensor and to uniquely distinguish paraoxon in mixed solutions containing carbofuran. The presented approach promises a new perspective for “real world” analyses and opens a new area of discriminative determination of various species in multicomponent solutions.

James R. Wild

Papers

The development of a new biosensor based on recombinant E. coli for the direct detection of organophosphorus neurotoxins.

Biotransformation patterns of 2,4,6-trinitrotoluene by aerobic bacteria

Enzymatic Hydrolysis of the Chemical Warfare Agent VX and its Neurotoxic Analogues by Organophosphorus Hydrolase

A New Approach For Discriminative Detection of Organophosphate Neurotoxins in the Presence of Other Cholinesterase Inhibitors

A Novel, Enzyme-Based Method for the Wound-Surface Removal and Decontamination of Organophosphorus Nerve Agents