Selective oxidation of sulfur mustard gas (HD) to non-toxic sulfoxide by the visible-light-catalyzed generation of singlet oxygen (1O2) is a promising degradation strategy. Although PCN-224 can absorb visible light, it suffers from rapid electron-hole recombination and low redox capacity, which limits the performance of HD degradation. Titanium dioxide (TiO2) is an excellent photocatalyst but it lacks visible-light-activity in degrading HD. In this study, PCN-224@TiO2 heterojunction with S-type core-shell structure was synthesized by in-situ growth method to prolong the visible light absorption capacity of TiO2 and inhibit the rapid recombination of PCN-224. The interface formation and internal electric field were optimized by adjusting the Zr/Ti ratio to enhance the charge transfer, redox capacity, electron-hole separation, and visible light absorption. In this study, the formation of heterojunction composites based on Zr-O-Ti linkages is demonstrated by a series of characterization methods. It is demonstrated by experiments and theoretical calculations that PCN-224@TiO2 can generate nearly 100 % 1O2 under visible light conditions without a sacrificial agent, resulting in efficient and selective oxidation of 2-chloroethyl ethyl sulfide (CEES), a simulant of HD, to non-toxic sulfoxide form.

The tetratopic linker, 1,3,6,8-tetrakis(p-benzoic acid)pyrene (H4 TBAPy) along with rare-earth (RE) ions is used for the synthesis of 9 isostructures of a metal-organic framework (MOF) with shp topology, named RE-CU-10 (RE = Y(III), Gd(III), Tb(III), Dy(III), Ho(III), Er(III), Tm(III), Yb(III), and Lu(III)). The synthesis of each RE-CU-10 analogue requires different reaction conditions to achieve phase pure products. Single crystal X-ray diffraction indicates the presence of a RE9 -cluster in Y- to Tm-CU-10, while a RE11 -cluster is observed for Yb- and Lu-CU-10. The photooxidation performance of RE-CU-10 analogues is evaluated, observing competition between linker-to-metal energy transfer versus the generation of singlet oxygen. The singlet oxygen produced is used to detoxify a mustard gas simulant 2-chloroethylethyl sulfide, with half-lives ranging from 4.0 to 5.8 min, some of the fastest reported to date using UV-irradiation and < 1 mol% catalyst, in methanol under O2 saturation.

Plasmonic nanostructures have attracted increasing interest in the fields of photochemistry and photocatalysis for their ability to enhance reactivity and tune reaction selectivity, a benefit of their strong interactions with light and their multiple energy decay mechanisms. Here we introduce the use of earth-abundant plasmonic aluminum nanoparticles as a promising renewable detoxifier of the sulfur mustard simulant 2-chloroethylethylsulfide through gas phase photodecomposition. Analysis of the decomposition products indicates that C-S bond breaking is facilitated under illumination, while C-Cl breaking and HCl elimination are favored under thermocatalytic (dark) conditions. This difference in reaction pathways illuminates the potential of plasmonic nanoparticles to tailor reaction selectivity toward less hazardous products in the detoxification of chemical warfare agents. Moreover, the photocatalytic activity of the Al nanoparticles can be regenerated almost completely after the reaction concludes through a simple surface treatment.

Zirconium-based metal-organic frameworks (Zr-MOFs) have been considered as prospective materials for the degradation of nerve chemical warfare agents (CWAs) but show poor catalytic performance toward blister agents. Moreover, the powder issues and the poor adsorption capability also remain as the major challenges for the application of Zr-MOFs in practical CWA detoxification. Herein, a series of defected granular UiO-66-NH2 metal-organic gels are synthesized via adjusting the amount of added concentrated hydrochloric acid for the decontamination of 2-chloroethyl ethyl sulfide (2-CEES), a sulfur mustard simulant. The half-life of 2-CEES decontaminated by defected granular UiO-66-NH2 metal-organic gels can be shortened to 7.6 min, which is the highest reported value for MOFs under ambient conditions. The mechanism of decontamination is that the amino group on the linkers in UiO-66-NH2 MOGs undergoes a substitution reaction with 2-CEES to yield 2-(2-(ethylthio)ethylamino)terephthalic acid, which is less toxic and fixed in the frameworks. The recycling test corroborates that the granular UiO-66-NH2 xerogels possess good stability and reusability. Static adsorption and desorption tests show that UiO-66-NH2 xerogels possess a high 2-CEES vapor adsorption capacity of 802 mg/g after exposure for 1 d and only 28 wt % desorption capacity after air exposure for 7 d. The dual function of ultrafast degradation and high adsorption capability provide a firm foundation for using UiO-66-NH2 xerogels as a future protection media.

Robust materials capable of heterogeneous reactivity are valuable for addressing toxic chemical clean up. Synthetic manipulations for generating titanium oxide nanomaterials have been utilized to alter both photochemical (1000 nm > λ > 400 nm) and chemical heterogeneous reactivity with 2-chloroethyl ethyl sulfide (2-CEES). Synthesizing TiO2 nanomaterials in the presence of long-chain alkylphosphonic acids enhanced the visible light-driven oxidation of the thioether sulfur of 2-CEES. Photooxidation reaction rates of 99 and 168 μmol/g/h (quantum yields of 5.07 × 10-4 and 8.58 × 10-4 molecules/photon, respectively) were observed for samples made with two different alkylphosphonic acids (C14H29PO3H2 and C9H19PO3H2, respectively). These observations are correlated with (i) generation of new surface defects/states (i.e., oxygen vacancies) as a result of TiO2 grafting by alkylphosphonic acid that may serve as reaction active sites, (ii) better light absorption by assemblies of nanorods and nanowires in comparison to individual nanorods, (iii) surface area differences, and (iv) the exclusion of OH groups due to the surface functionalization with alkylphosphonic acids via Ti-O-P bonds on the TiO2. Alternatively, nanowire-form H2Ti2O5·H2O was produced and found to be capable of highly efficient hydrolysis of the carbon-chlorine (C-Cl) bond of 2-CEES in the dark with a reaction rate of 279.2 μmol/g/h due to the high surface area and chemical nature of the titanate structure.

2-chloroethyl ethyl sulfide (CEES) is a vesicant agent, commonly referred to half mustard due to its ability to form monofunctional adducts with DNA. In this study, we evaluated the chemoprotective potential of 13 compounds and their mixtures with sodium 2-mercaptoethanesulfonate (MESNA) against CEES-induced geno- and cytotoxicity in human lung cell line A-549. MESNA, L-glutathione (GSH), thiourea, sodium thiosulfate, hexamethylenetetramine, 4-acetamidophenol, asoxime dichloride (HI-6), N-acetyl-L-cysteine (NAC), sodium pyruvate, myo-inositol, 3-aminobenzamide (3-AB), nicotinamide, and Nω-nitro-L-arginine methyl ester hydrochloride and combinations of these compounds with MESNA were applied 30 min before CEES. DNA alkylation was measured using modified comet assay 1 and 24 h after the exposure. Cell viability was determined using MTT assay at 24 and 72 h. The mono-therapeutical approach identified MESNA and GSH to provide significant chemoprotection. NAC and 3-AB supported DNA damage repair, while cell viability remained unaffected. Mixtures of GSH or NAC with MESNA showed protective synergism against DNA damage. Other compounds or their combinations with MESNA failed due to the potentiation of CEES-induced cytotoxicity. The chemoprotection against CEES remains limited; however, the combination of substances can provide protective synergy and may represent a promising strategy in the treatment of accidental exposure to monoalkylating agents.

Atmospheric pressure plasma jet (APPJ) were used to decontaminate the surface\'s 2-Chloroethyl ethyl sulfide (2-CEES), a kind of sulfur mustard (HD) simulant. The power of the APPJ device didn\'t exceed 7.77 W. Helium APPJ was easier to generate plasma jet than argon APPJ. The treated nude mouse skin surface\'s temperature slowly reached 30.4 °C and no obvious lesions in the dermis and skin appendages after 15 min treatment. Compared with argon APPJ, the helium APPJ produced more ·OH and the maximum concentration of ·OH was 3.748 × 10-9 mol/L. Attributed to the low density and more ·OH content, the helium APPJ had a better decontamination effect. With a maximum voltage of 7 kV and a helium flow rate of 4 L/min, 2-CEES (4.53 mg/cm2) can be completely decontaminated in 2.5 min, and no gaseous 2-CEES was detected. The detection of the 2-Hydroxyethyl ethyl sulfide proved the role of ·OH in the reaction system. During the reaction, 2-Chloroethyl ethyl sulfoxide and 2-Chloroethyl ethyl sulfone were also detected. The plasma jet could reduce the toxicity by destroying the parent molecule (2-CEES) in a short time, but it took more time to eliminate the intermediate products. No relevant intermediate products were detected in the gaseous, ensured the safety of personnel operating in open spaces.

The mitochondrion has a substantial role in innate immunity and inflammasome signaling pathways. Sulfur mustard (SM) induces toxicity in cytoplasmic organelles. We aimed to evaluate the potential therapeutic effect of curcumin on the toxicity of SM analog through measuring gene expression levels of mitochondrial dynamics followed by induction of the inflammasome signaling pathway. After the treatment of pulmonary epithelial cell line (A549) by 2-chloroethyl ethyl sulfide (CEES) (2500 mM) for 48h, the transcriptional activity of mitochondrial fission and fusion genes such as dynamin-related protein 1 (Drp1), mitochondrial fission 1 protein (Fis1), mitofusin-1 (Mfn1), mitofusin-2 (Mfn2), and Dominant optic atrophy (Opa1) and inflammasome pathway genes including absent in melanoma 2 (AIM2), NLR family containing protein 3 (NLRP3), and Apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) was measured. Furthermore, the inhibitory effect of curcumin (160 mM) concurrent with SM analog on the expression level of mitochondria and inflammasome genes was investigated. CEES was able to over-express the fission, fusion (Drp1 ~ 8, Fis1 4.5, Mfn2 15, and Opa1 16-fold) and inflammasome genes (AIM2, NLRP3,  8 and 6-fold, respectively), whereas Mfn1 was significantly decreased (0.5-fold) and a not statistically significant decrease was observed in the ASC gene. Curcumin could modulate the effect of CEES, mitigate the expression of fission, fusion, and inflammasome genes exceedingly. However, a major increase in the repairer fusion gene (Mfn1, 6-fold) and complete suppression of the ASC gene were the outcomes of using the curcumin. In conclusion, we suggest curcumin alleviates the disturbance of mitochondrial dynamics and downregulates the inflammasome genes exposed to the CEES.

Sulfur mustard, a chemical warfare agent known to be a vesicant of skin, readily diffuses in the blood stream and reaches internal organs. In the present study, we used the analog (2-chloroethyl)-ethyl-sulfide (CEES) to provide novel data on the systemic diffusion of vesicants and on their ability to induce brain damage, which result in neurological disorders. SKH-1 hairless mice were topically exposed to CEES and sacrificed at different time until 14 days after exposure. A plasma metabolomics study showed a strong systemic impact following a self-protection mechanism to alleviate the injury of CEES exposure. This result was confirmed by the quantification of specific biomarkers in plasma. Those were the conjugates of CEES with glutathione (GSH-CEES), cysteine (Cys-CEES) and N-acetyl-cysteine (NAC-CEES), as well as the guanine adduct (N7Gua-CEES). In brain, N7Gua-CEES could be detected both in DNA and in organ extracts. Similarly, GSH-CEES, Cys-CEES and NAC-CEES were present in the extracts until day14. Altogether, these results, based on novel exposure markers, confirm the ability of vesicants to induce internal damage following dermal exposure. The observation of alkylation damage to glutathione and DNA in brain provides an additional mechanism to the neurological insult of SM.

Sulfur Mustard (SM) induces cell injury via exerting oxidative stress, protease-anti protease imbalance, and inflammation. Inflammasome as one part of innate immunity has a critical role in the recognition of cell injuries and the initiation of the inflammation process by releasing IL-1β. Hence, the present study investigated the effects of the sub-lethal doses of 2-chloroethyl ethyl sulfide (CEES) as SM analog on the gene expression level of inflammasome-related genes as well as the potential protective effects of curcumin on this process. The effects of sub-lethal doses (500, 1000, and 2500 mM) of CEES on pulmonary epithelial cell line (A549) were determined at various time points (12, 24, and 48 h). Following the treatment of cells with CEES, the kinetic alterations of the expression levels of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-ĸB1), NLR family pyrin domain containing 1 (NLRP1), Caspase-1 (Casp1), and Interleukin-1β (IL-1β)  genes were analyzed; using real-time PCR. In addition, the concurrent protective effects of different doses of curcumin (20, 40, 80, and 160 mM) on modulating the effects of CEES were studied. Although it was found that the lowest sub-lethal dose of CEES (500 mM) was able to up-regulate the inflammasome-related genes, the maximum alterations occurred 48 h after the treatment with the higher sub-lethal dose (2500 mM) of CEES. The maximum alteration occurred in Casp1 (38 fold), IL-1β (19 fold), and NLRP1 (~4 fold) genes (p<0.0001). However, the NF-ĸB gene expression level did not alter following CEES exposure. Even though low doses of curcumin (20, 40, and 80 mM) were able to down-regulate the studied genes, it was found that the treatment of cells with 160 mM of curcumin for 48 h was able to normalize the expression level of all genes. The present study concludes that curcumin as an anti-inflammatory agent may have beneficial immunomodulatory effects following CEES exposure.