In-situ detoxification of schedule-I chemical warfare agents utilizing Zr(OH)4@W-ACF functional material for the development of next generation NBC protective gears.

Chemical warfare agents (CWAs) have become a pivotal concern for the global community and spurred a wide spectrum of research for the development of new generation protective materials. Herein, a highly effective self-detoxifying filter consisting of in-situ immobilized Zirconium hydroxide [Zr(OH)4] over woven activated carbon fabric [Zr(OH)4@W-ACF] is presented for the removal of CWAs. It was prepared to harness the synergistic effect of high surface area of W-ACF, leads to high dispersion of CWAs and high phosphilicity and reactivity of [Zr(OH)4]. The synthesized materials were characterized by ATR-FTIR, EDX, SEM, TEM, XPS, TGA, and BET surface area analyzer. The kinetics of  in-situ degradation of CWAs over Zr(OH)4@W-ACF were studied and found to be following the first-order reaction kinetics. The rate constant was found to be 0.244 min-1 and 2.31 × 10-2 min-1 for sarin and soman, respectively over Zr(OH)4@W-ACF. The potential practical applicability of this work was established by fabricating Zr(OH)4@W-ACF as reactive adsorbent layer for protective suit, and found to be meeting the specified criteria in terms of air permeability, tearing strength and nerve agent permeation as per TOP-08-2-501A:2013 and IS-17380:2020. The degradation products of CWAs were analyzed with NMR and GC-MS. The combined properties of dual functional textile with reactive material are expected to open up new exciting avenues in the field of CWAs protective clothing and thus find diverse application in defence and environmental sector.

Screening of core filter layer for the development of respiratory mask to combat COVID-19.

The severe outbreak of respiratory coronavirus disease 2019 has increased the significant demand of respiratory mask and its use become ubiquitous worldwide to control this unprecedented respiratory pandemic. The performance of a respiratory mask depends on the efficiency of the filter layer which is mostly made of polypropylene melt blown non-woven (PP-MB-NW). So far, very limited characterization data are available for the PPE-MB-NW in terms to achieve desired particulate filtration efficiency (PFE) against 0.3 µm size, which are imperative in order to facilitate the right selection of PP-MB-NW fabric for the development of mask. In present study, eight different kinds of PP-MB-NW fabrics (Sample A-H) of varied structural morphology are chosen. The different PP-MB-NW were characterized for its pore size and distribution by mercury porosimeter and BET surface area analyzer was explored first time to understand the importance of blind pore in PFE. The PP-MB-NW samples were characterized using scanning electron microscopy so as to know the surface morphology. The filtration efficiency, pressure drop and breathing resistance of various PP-MB-NW fabric samples are investigated in single and double layers combination against the particle size of 0.3, 0.5 and 1 µm. The samples which are having low pore dia, high solid fraction volume, and low air permeability has high filtration efficiency (> 90%) against 0.3 µm particle with high pressure drop (16.3-21.3 mm WC) and breathing resistance (1.42-1.92 mbar) when compared to rest of the samples. This study will pave the way for the judicial selection of right kind of filter layer i.e., PP-MB-NW fabric for the development of mask and it will be greatly helpful in manufacturing of mask in this present pandemic with desired PFE indicating considerable promise for defense against respiratory pandemic.

Luminol-Based Turn-On Fluorescent Sensor for Selective and Sensitive Detection of Sulfur Mustard at Ambient Temperature.

We have explored a novel turn-on fluorescence detection of sulfur mustard (SM) at "room temperature". The innovative protocol that uses the combination of luminol and an ionic liquid in water exhibits fluorescence detection of SM within seconds. In this simple, fast, and low-cost chemosensing method, luminol acts as the receptor as well as a signaling element, and the ionic liquid (1-ethyl-3-methylimidazolium dicyanamide) provides the requisite and polarizing medium to realize the detection at "room temperature". Interestingly, with a higher concentration of a probe (0.56 mM), SM sensing can be visualized with the naked eye, leading to the formation of a fluorescent green color within a minute, thus expanding the application of the developed sensing technique for chromo-fluorogenic detection of SM. Excellent selectivity, sensitivity (LOD: 6 ppm), and chemosensing at ambient temperature make this methodology completely field-deployable.

Surface plasmon resonance sensing of Ebola virus: a biological threat.

Here, different monoclonal antibodies (mAb1, mAb2 and mAb3) of Ebola virus were screened in a real-time and label-free manner using surface plasmon resonance (SPR) to select an appropriate antibody for biosensor applications against a biological warfare agent. For this purpose, a gold SPR chip was modified with 4-mercaptobenzoic acid (4-MBA), and modification was confirmed by FTIR-ATR and EIS. The 4-MBA-modified gold SPR chip was used for immobilization of the recombinant nucleoprotein of Ebola (EBOV-rNP), and the interactions of mAb1, mAb2 and mAb3 were then investigated to determine the best mAb based on the affinity constant (KD), expressed as equilibrium dissociation constant. KD values of 809 nM, 350 pM and 52 pM were found for the interaction of mAb1, mAb2 and mAb3 of Ebola with the immobilized EBOV-rNP, respectively, thus reflecting the high affinity of mAb3. This was confirmed by ELISA results. The thermodynamic parameters (ΔG, ΔH and ΔS) for the interaction between mAb3 and EBOV-rNP were also determined, which revealed that the interaction was spontaneous, endothermic and driven by entropy. The SPR limit of detection of EBOV-rNP with mAb3 was 0.5 pg ml-1, showing mAb3 to be the best high-affinity antibody in our study. This study has opened up new possibilities for SPR screening of different monoclonal antibodies of BWA through the convergence of materials science and optical techniques.

Photoelectrocatalytic degradation of vesicant agent using Eu/ZnO/pPy nanocomposite.

Herein, we demonstrate a nanocomposite material Eu/ZnO/pPy for enhanced performance in photoelectrocatalytic degradation of chemical warfare agent sulphur mustard (SM) at ambient conditions which is growing concern of the Scientific Community amidst the current climate of terrorism. Eu/ZnO/pPy was electrochemically prepared on Au electrode at ambient conditions and was used for electrocatalytic reductive elimination of chloride from SM and results indicated one electron involvement process for the cleavage of the carbon-chloride bond. Surface morphology of Eu/pPy, ZnO/pPy and Eu/ZnO/pPy composites were characterized by SEM and confirmed the formation of the nanoparticles and nanorods on the modified electrode which leads to provide more surface area for the reductive elimination reaction. The elemental composition, functional groups and phase of materials on the modified electrode were deduced using EDX, Raman spectroscopy and XRD, respectively. Eu/ZnO/pPy/Au electrode was utilized for the photoelectrocatalytic degradation of SM as it exhibit excellent electrocatalytic activity and degradation products were analyzed by GC-MS. In the reductive elimination of SM, the following parameters were deduced (i) heterogeneous rate constant (0.127 s-1), (ii) transfer coefficient (0.32) and (iii) number of electron involved (1.0). The enhanced photoelectrocatalytic capability of this nanocomposite could serve as a novel and promising catalyst in defence and environmental applications.

Synthesis and biological evaluation of some novel 1-substituted fentanyl analogs in Swiss albino mice.

Fentanyl [N-(1-phenethyl-4-piperidinyl)propionanilide] is a potent opioid analgesic agent, but a has narrow therapeutic index. We reported earlier on the synthesis and bioefficacy of fentanyl and its 1-substituted analogs (1-4) in mice. Here we report the synthesis and biological evaluation of four additional analogs, viz. N-isopropyl-3-(4-(N-phenylpropionamido)piperidin-1-yl)propanamide (5), N-t-butyl-3-(4-(N-phenylpropionamido)piperidin-1-yl)propanamide (6), isopropyl 2-[4-(N-phenylpropionamido)piperidin-1-yl]propionate (7) and t-butyl 2-[4-(N-phenylpropionamido)piperidin-1-yl]propionate (8). The median lethal dose (LD50) determined by intravenous, intraperitoneal and oral routes suggests these analogs to be comparatively less toxic than fentanyl. On the basis of observational assessment on spontaneous activities of the central, peripheral, and autonomic nervous systems, all the analogs were found to be similar to fentanyl. Naloxone hydrochloride abolished the neurotoxic effects of these analogs, thereby ascertaining their opioid receptor-mediated effects. All the analogs displayed significant analgesic effects, measured by formalin-induced hind paw licking and tail immersion tests at their respective median effective dose (ED50). They also exhibited 8-12 fold increase in therapeutic index over fentanyl. However, 5 and 6 alone produced lower ED50 (20.5 and 21.0 µg/kg, respectively) and higher potency ratio (1.37 and 1.33, respectively) compared to fentanyl. They could thus be considered for further studies on pain management.

Effect of exposure to fentanyl aerosol in mice on breathing pattern and respiratory variables.

The breathing pattern of mice that were exposed to fentanyl aerosol was studied (2.7, 5.7, 6.0, 10.0, and 23.6 microg/m(3); for 1 hour), using dimethyl sulfoxide as a vehicle. This study was conducted in a head-only exposure assembly. Body plethysmographs connected to a volumetric pressure transducer were used to capture the respiratory signals, and an on-line computer program capable of recognizing the changes in the breathing pattern was used for monitoring the respiratory pattern. The response of mice to fentanyl exposure was found to be concentration dependent. A lower concentration (2.7 microg/m(3)) showed fast recovery and no mortality, while 100% mortality was observed at a higher concentration (23.6 microg/m(3)). No sensory, pulmonary irritation, and airway limitation in mice was observed, and death occurred probably due to respiratory depression. The concentration that decreased 50% of the respiratory frequency (RD(50)) was estimated to be 6.4 microg/m(3). The extrapolated human threshold limit value, calculated from the RD(50) value, was found to be 0.192 microg/m(3). The concentration that caused 50% mortality in exposed mice (LC(50)) was estimated to be 8.8 microg/m(3). This study shows that aerosolized fentanyl does not cause sensory and pulmonary irritation, and since the RD(50) and LC(50) are very close with a low safety margin, this type of sedative should not be used as an incapacitating agent.

A quantitative NMR protocol for the simultaneous analysis of atropine and obidoxime in parenteral injection devices.

A rapid selective and accurate quantitative (1)H NMR method was developed for the simultaneous analysis of obidoxime chloride and atropine sulfate, the active components in parenteral injection devices (PID) used for the emergency treatment of poisoning by toxic organophosphates. The spectra were acquired in 90% H(2)O-10% D(2)O using sodium 3-(trimethylsilyl)-1-propane sulfonate hydrate as the internal standard. Both synthetic mixtures and dosage forms were assayed. The results were compared with those obtained from a reported HPLC method.

Impregnated silica nanoparticles for the reactive removal of sulphur mustard from solutions.

High surface area (887.3m(2)/g) silica nanoparticles were synthesized using aerogel route and thereafter, characterized by N(2)-Brunauer-Emmet-Teller (BET), SEM and TEM techniques. The data indicated the formation of nanoparticles of silica in the size range of 24-75 nm with mesoporous characteristics. Later, these were impregnated with reactive chemicals such as N-chloro compounds, oxaziridines, polyoxometalates, etc., which have already been proven to be effective against sulphur mustard (HD). Thus, developed novel mesoporous reactive sorbents were tested for their self-decontaminating feature by conducting studies on kinetics of adsorptive removal of HD from solution. Trichloroisocyanuric acid impregnated silica nanoparticles (10%, w/w)-based system was found to be the best with least half-life value (t(1/2)=2.8 min) among prepared systems to remove and detoxify HD into nontoxic degradation products. Hydrolysis, dehydrohalogenation and oxidation reactions were found to be the route of degradation of HD over prepared sorbents. The study also inferred that 10% loading of impregnants over high surface area and low density silica nanoparticles enhances the rate of reaction kinetics and seems to be useful in the field of heterogeneous reaction kinetics.

Gas chromatographic retention indices of fentanyl and analogues.

Narcotic analgesics of the fentanyl class are characterized by high potency and relatively short duration of action. These compounds nowadays have become a substitute for heroine and are highly addictive for abusers. Herein, we report retention indices of fentanyl and its eighteen analogues relative to the homologous n-alkane series. These values are determined on a moderately polar BP-5 capillary column under programmed temperature and isothermal chromatographic conditions. The analogues differ in the substituent attached to the piperidine ring nitrogen, and retention indices are found to vary according to the nature of the substituent. The effects of chromatographic conditions like temperature programming rate, carrier gas flow rate, and oven temperature are studied. Retention indices are also determined on a non-polar BP-1 column to study the influence of stationary phase polarity. Standard deviation of all the RI values is less than one index unit.

Use of single-drop microextraction for determination of fentanyl in water samples.

Fentanyl is a very potent synthetic narcotic analgesic. Because of its strong sedative properties, it has become an analogue of illicit drugs such as heroin. Its unambiguous detection and identification in environmental samples can be regarded as strong evidence of its illicit preparation. In this paper we report application of single-drop microextraction (SDME) for analysis of water samples spiked with fentanyl. Experimental conditions which affect the performance of SDME, for example the nature of the extracting solvent, sample stirring speed, extraction time, ionic strength, and solution pH, were optimized. The method was found to be linear in the concentration range 0.10-10 ng mL(-1). The limits of quantitation and detection of the method were 100 pg mL(-1) and <75 pg mL(-1), respectively. This technique is superior to other sample-preparation techniques because of the simple experimental set-up, short analysis time, high sensitivity, and minimum use of organic solvent.