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Food Chemistry Aug 2023Herein, we developed a method coupling TLC and enzyme inhibition principles to rapidly detect OPs (dichlorvos, paraoxon and parathion). After the removal of the organic...
Herein, we developed a method coupling TLC and enzyme inhibition principles to rapidly detect OPs (dichlorvos, paraoxon and parathion). After the removal of the organic solvent from the samples using TLC and paper-based chips, the enzyme was added to the detection system. The results showed that the current method effectively reduced the effects of solvents on enzyme behavior. Moreover, the pigments could be successfully retained on TLC with 40% ddHO/ACN solution (v/v) as a developing solvent. Additionally, the detection limits (LODs) were 0.002 µg/mL for dichlorvos, 0.006 µg/mL for paraoxon, and 0.003 µg/mL for parathion. Finally, the method was applied to spiked cabbage, cucumber, and spinach and showed good average recoveries ranging between 70.22% and 119.79%. These results showed that this paper-based chip had high sensitivity, precleaning, and elimination of organic solvent properties. Furthermore, it provides a valuable idea for sample pretreatment and rapid determination of pesticide residues in food.
Topics: Pesticides; Dichlorvos; Chromatography, Thin Layer; Paraoxon; Pesticide Residues; Parathion; Solvents
PubMed: 36893638
DOI: 10.1016/j.foodchem.2023.135822 -
Mikrochimica Acta Mar 2023A liquid crystal-based assay (LC) was developed to monitor paraoxon by incorporating a Cu -coated substrate and the inhibitory effect of paraoxon with...
A liquid crystal-based assay (LC) was developed to monitor paraoxon by incorporating a Cu -coated substrate and the inhibitory effect of paraoxon with acetylcholinesterase (AChE). We observed that thiocholine (TCh), a hydrolysate of AChE and acetylthiocholine (ATCh), interfered with the alignment of 5CB films through a reaction between Cu ions and the thiol moiety of TCh. The catalytic activity of AChE was inhibited in the presence of paraoxon due to the irreversible interaction between TCh and paraoxon; consequently, no TCh molecule was available to interact with Cu on the surface. This resulted in a homeotropic alignment of the liquid crystal. The proposed sensor platform sensitively quantified paraoxon with a detection limit of 2.20 ± 0.11 (n = 3) nM within a range of 6 to 500 nM. The specificity and reliability of the assay were verified by measuring paraoxon in the presence of various suspected interfering substances and spiked samples. As a result, the sensor based on LC can potentially be used as a screening tool for accurate evaluation of paraoxon and other organophosphorus compounds.
Topics: Paraoxon; Pesticides; Acetylcholinesterase; Cholinesterase Inhibitors; Reproducibility of Results; Liquid Crystals
PubMed: 36890280
DOI: 10.1007/s00604-023-05716-z -
Analytical Chemistry Mar 2023Peroxidase-mimetic materials are intensively applied to establish multienzyme systems because of their attractive merits. However, almost all of the nanozymes explored...
Amorphous Fe-Containing Phosphotungstates Featuring Efficient Peroxidase-like Activity at Neutral pH: Toward Portable Swabs for Pesticide Detection with Tandem Catalytic Amplification.
Peroxidase-mimetic materials are intensively applied to establish multienzyme systems because of their attractive merits. However, almost all of the nanozymes explored exhibit catalytic capacity only under acidic conditions. The pH mismatch between peroxidase mimics in acidic environments and bioenzymes under neutral conditions significantly restricts the development of enzyme-nanozyme catalytic systems especially for biochemical sensing. To solve this problem, here amorphous Fe-containing phosphotungstates (Fe-PTs) featuring high peroxidase activity at neutral pH were explored to fabricate portable multienzyme biosensors for pesticide detection. The strong attraction of negatively charged Fe-PTs to positively charged substrates as well as the accelerated regeneration of Fe by the Fe/W bimetallic redox couples was demonstrated to play important roles in endowing the material with peroxidase-like activity in physiological environments. Consequently, integrating the developed Fe-PTs with acetylcholinesterase and choline oxidase led to an enzyme-nanozyme tandem platform with good catalytic efficiency at neutral pH for organophosphorus pesticide response. Furthermore, they were immobilized onto common medical swabs to fabricate portable sensors for paraoxon detection conveniently based on smartphone sensing, showing excellent sensitivity, good anti-interference capacity, and low detection limit (0.28 ng/mL). Our contribution expands the horizon of acquiring peroxidase activity at neutral pH, and it will also open avenues to construct portable and effective biosensors for pesticides and other analytes.
Topics: Pesticides; Organophosphorus Compounds; Acetylcholinesterase; Peroxidase; Oxidoreductases; Peroxidases; Hydrogen-Ion Concentration; Biosensing Techniques; Hydrogen Peroxide
PubMed: 36862973
DOI: 10.1021/acs.analchem.3c00008 -
International Journal of Molecular... Feb 2023Combined use of various antimicrobial peptides (AMPs) with enzymes that hydrolyze the signaling molecules of the resistance mechanism of various microorganisms, quorum...
Combined use of various antimicrobial peptides (AMPs) with enzymes that hydrolyze the signaling molecules of the resistance mechanism of various microorganisms, quorum sensing (QS), to obtain effective antimicrobials is one of the leading approaches in solving the antimicrobial resistance problem. Our study investigates the lactoferrin-derived AMPs, lactoferricin (Lfcin), lactoferampin and Lf(1-11), as potential partners for combination with enzymes hydrolyzing lactone-containing QS molecules, the hexahistidine-containing organophosphorus hydrolase (His-OPH) and penicillin acylase, to obtain effective antimicrobial agents with a scope of practical application. The possibility of the effective combination of selected AMPs and enzymes was first investigated in silico using molecular docking method. Based on the computationally obtained results, His-OPH/Lfcin combination was selected as the most suitable for further research. The study of physical-chemical characteristics of His-OPH/Lfcin combination revealed the stabilization of enzymatic activity. A notable increase in the catalytic efficiency of action of His-OPH in combination with Lfcin in the hydrolysis of paraoxon, -(3-oxo-dodecanoyl)-homoserine lactone and zearalenone used as substrates was established. Antimicrobial efficiency of His-OPH/Lfcin combination was determined against various microorganisms (bacteria and yeasts) and its improvement was observed as compared to AMP without enzyme. Thus, our findings demonstrate that His-OPH/Lfcin combination is a promising antimicrobial agent for practical application.
Topics: Quorum Sensing; Lactoferrin; Molecular Docking Simulation; Peptides; Anti-Infective Agents
PubMed: 36834977
DOI: 10.3390/ijms24043566 -
Biosensors Feb 2023Analytical methods for detecting neurotransmitters (NTs) and organophosphorus (OP) pesticides with high sensitivity are vitally necessary for the rapid identification of...
Analytical methods for detecting neurotransmitters (NTs) and organophosphorus (OP) pesticides with high sensitivity are vitally necessary for the rapid identification of physical, mental, and neurological illnesses, as well as to ensure food safety and safeguard ecosystems. In this work, we developed a supramolecular self-assembled system (SupraZyme) that exhibits multi-enzymatic activity. SupraZyme possesses the ability to show both oxidase and peroxidase-like activity, which has been employed for biosensing. The peroxidase-like activity was used for the detection of catecholamine NTs, epinephrine (EP), and norepinephrine (NE) with a detection limit of 6.3 µM and 1.8 µM, respectively, while the oxidase-like activity was utilized for the detection of organophosphate pesticides. The detection strategy for OP chemicals was based on the inhibition of acetylcholine esterase (AChE) activity: a key enzyme that is responsible for the hydrolysis of acetylthiocholine (ATCh). The corresponding limit of detection of paraoxon-methyl (POM) and methamidophos (MAP) was measured to be 0.48 ppb and 15.8 ppb, respectively. Overall, we report an efficient supramolecular system with multiple enzyme-like activities that provide a versatile toolbox for the construction of sensing platforms for the colorimetric point-of-care detection of both NTs and OP pesticides.
Topics: Pesticides; Organophosphorus Compounds; Colorimetry; Ecosystem; Acetylcholinesterase; Oxidoreductases; Metals; Biosensing Techniques; Peroxidases
PubMed: 36832043
DOI: 10.3390/bios13020277 -
Journal of Neurochemistry Apr 2024Millions of individuals globally suffer from inadvertent, occupational or self-harm exposures from organophosphate (OP) insecticides, significantly impacting human...
A single post-exposure oxime RS194B treatment rapidly reactivates acetylcholinesterase and reverses acute symptoms in macaques exposed to diethylphosphorothioate parathion and chlorpyrifos insecticides.
Millions of individuals globally suffer from inadvertent, occupational or self-harm exposures from organophosphate (OP) insecticides, significantly impacting human health. Similar to nerve agents, insecticides are neurotoxins that target and inhibit acetylcholinesterase (AChE) in central and peripheral synapses in the cholinergic nervous system. Post-exposure therapeutic countermeasures generally include administration of atropine with an oxime to reactivate the OP-inhibited AChE. However, animal model studies and recent clinical trials using insecticide-poisoned individuals have shown minimal clinical benefits of the currently approved oximes and their efficacy as antidotes has been debated. Currently used oximes either reactivate poorly, do not readily cross the blood-brain barrier (BBB), or are rapidly cleared from the circulation and must be repeatedly administered. Zwitterionic oximes of unbranched and simplified structure, for example RS194B, have been developed that efficiently cross the BBB resulting in reactivation of OP-inhibited AChE and dramatic reversal of severe clinical symptoms in mice and macaques exposed to OP insecticides or nerve agents. Thus, a single IM injection of RS194B has been shown to rapidly restore blood AChE and butyrylcholinesterase (BChE) activity, reverse cholinergic symptoms, and prevent death in macaques following lethal inhaled sarin and paraoxon exposure. The present macaque studies extend these findings and assess the ability of post-exposure RS194B treatment to counteract oral poisoning by highly toxic diethylphosphorothioate insecticides such as parathion and chlorpyrifos. These OPs require conversion by P450 in the liver of the inactive thions to the active toxic oxon forms, and once again demonstrated RS194B efficacy to reactivate and alleviate clinical symptoms within 60 mins of a single IM administration. Furthermore, when delivered orally, the Tmax of RS194B at 1-2 h was in the same range as those administered IM but were maintained in the circulation for longer periods greatly facilitating the use of RS194B as a non-invasive treatment, especially in isolated rural settings.
Topics: Animals; Mice; Acetamides; Acetylcholinesterase; Butyrylcholinesterase; Chlorpyrifos; Cholinesterase Inhibitors; Cholinesterase Reactivators; Insecticides; Macaca; Nerve Agents; Organophosphorus Compounds; Oximes; Parathion
PubMed: 36786545
DOI: 10.1111/jnc.15777 -
Applied Biochemistry and Biotechnology Jul 2023This paper proposes a fabrication of a hyper-sensitive amperometric biosensor for paraoxon-ethyl (PE) detection. In this developed biosensor, polyaniline (PANI) and...
This paper proposes a fabrication of a hyper-sensitive amperometric biosensor for paraoxon-ethyl (PE) detection. In this developed biosensor, polyaniline (PANI) and copper oxide (CuO)-based nanocomposite is used as a sensing platform. The homogeneous distribution of CuO onto the PANI matrix enhances the surface area and conductivity of the nanocomposite. Additionally, the PANI produces a compatible environment for enzyme immobilization, which further enhances the rate of electron transfer. For biosensor fabrication, the nanocomposite is deposited electrophoretically onto the ITO glass substrate and immobilization of acetylcholinesterase (AChE) enzyme is conducted onto the fabricated electrode surface. The results validate good reproducibility, good stability, and high selectivity of the fabricated biosensor (AChE/PANI@CuO/ITO). The inhibition rate of paraoxon-ethyl (PE) is recorded in the concentration range of 1-200 nM with a low limit of detection of 0.096 nM or 96 pM. The sensitivity of the developed biosensor is found to be 49.86 µA(nM). The developed biosensor is further successfully accomplished for the detection of PE in real samples like rice and pulse.
Topics: Paraoxon; Copper; Acetylcholinesterase; Reproducibility of Results; Nanoparticles; Oxides; Biosensing Techniques; Enzymes, Immobilized
PubMed: 36701097
DOI: 10.1007/s12010-023-04350-y -
Environmental Science and Pollution... Mar 2023Water-insoluble organic pollutants in environment, such as sea oil spill, industrial reagents, and the abused organic pesticides, bring great risks to global water...
Water-insoluble organic pollutants in environment, such as sea oil spill, industrial reagents, and the abused organic pesticides, bring great risks to global water systems, which thus requires effective approaches for organic pollutant elimination. In this study, we report a catalytic metal-organic framework (MOF)-melamine foam (MF) composite material (DDT-UiO-66-NH@MF) showing excellent oil-water separation performance and enzyme-like degradation ability toward organophosphorus pesticides. The fabrication of DDT-UiO-66-NH@MF is based on the immobilization of a MOF-derived nanozyme (UiO-66-NH) on MF sponge, and followed by the hydrophobic modification of UiO-66-NH by 1-dodecanethiol (DDT). The obtained DDT-UiO-66-NH@MF thus displayed superhydrophobic/superhydrophilic property with a high water contact angle (WCA = 144.6°) and specific adsorption capacity toward various oils/organic solvents (62.2-119.8 g/g), which leads to a continuous oil-water separation on a simple device. In the meanwhile, owing to the enzyme-like property of UiO-66-NH, DDT-UiO-66-NH@MF also displayed good ability to hydrolyze paraoxon under mild conditions, which facilitates the elimination of toxic pesticide residuals in water systems. This work provides a simple, efficient, and green approach for the separation and treatment of water-insoluble organic pollutants, as well as expands the use of MOFs-MF sponge composite materials in environmental sustainability.
Topics: Metal-Organic Frameworks; Environmental Pollutants; DDT; Organophosphorus Compounds; Pesticides; Water; Water Pollutants
PubMed: 36689117
DOI: 10.1007/s11356-023-25441-7 -
RSC Advances Dec 2022In recent years, graphene quantum dots (GQDs) received huge attention due to their unique properties and potential applicability in different area. Here, we report...
In recent years, graphene quantum dots (GQDs) received huge attention due to their unique properties and potential applicability in different area. Here, we report simple and facile method for the synthesis of GQDs and their functionalization by doping and co-doping using different heteroatom under the optimized conditions. The doping and co-doping of GQDs using boron and nitrogen have been confirmed by FTIR and TEM. The UV-visible and fluorescence techniques have been used to study the optical properties and stability of functionalized GQDs. Further, the screening for enhancement of quantum yields of all GQDs were performed with fluorescence and UV-visible spectra under the optimized conditions. The average QY was obtained as 16.0%, 83.6%, 18.2% and 29.6% for GQDs, B-GQDs, N-GQDs and B,N-GQDs, respectively. The sensor was used to determine paraoxon in water samples. The LOD was observed to be 1.0 × 10 M with linearity range of 0.001 to 0.1 M. The RSD was calculated for the developed B,N-GQDs based sensor and observed to be 2.99% with the regression coefficient as 0.997. All the doped, co-doped and un-doped GQDs possess remarkable properties as a fluorescent probe.
PubMed: 36605643
DOI: 10.1039/d2ra05275j -
ACS Applied Nano Materials Dec 2022Nanoscale cerium-bismuth oxides/oxynitrates were prepared by a scalable low-temperature method at ambient pressure using water as the sole solvent. Solid solutions were...
Nanoscale cerium-bismuth oxides/oxynitrates were prepared by a scalable low-temperature method at ambient pressure using water as the sole solvent. Solid solutions were formed up to a 1:1 Ce/Bi molar ratio, while at higher doping levels, bismuth oxynitrate photocatalysts with a pronounced layered structure were formed. Bismuth caused significant changes in the structure and surface properties of nanoceria, such as the formation of defects, oxygen-containing surface groups, and Lewis and Brønsted acid sites. The prepared bifunctional adsorbents/photocatalysts were efficient in the removal of toxic organophosphate (methyl paraoxon) from water by reactive adsorption followed by photocatalytic decomposition of the parent compound and its degradation product (-nitrophenol). Bi-doped ceria also effectively adsorbed and photodegraded the endocrine disruptors bisphenols A and S and outperformed pure ceria and the P25 photocatalyst in terms of efficiency, durability, and long-term stability. The very low toxicity of Bi-nanoceria to mammalian cells, aquatic organisms, and bacteria has been demonstrated by comprehensive in vivo/in vitro testing, which, in addition to its simple "green" synthesis, high activity, and durability, makes Bi-doped ceria promising for safe use in abatement of toxic chemicals.
PubMed: 36583119
DOI: 10.1021/acsanm.2c03926