ABSTRACT
Tryptophan(Trp) is being explored as a potential biomarker for various diseases associated with decreased tryptophan levels; however, metabolomic methods are expensive and time-consuming and require extensive sample analysis, making them urgently needed for trace detection. To exploit the properties of Ti3C2 MXenes a rational porous methyl orange (MO)-delaminated Ti3C2 MXene was prepared via a facile mixing process for the electrocatalytic oxidation of Trp. The hollow-like 3D structure with a more open structure and the synergistic effect of MO and conductive Ti3C2 MXene enhanced its electrochemical catalytic capability toward Trp biosensing. More importantly, MO can stabilize Ti3C2 MXene nanosheets through noncovalent π-π interactions and hydrogen bonding. Compared with covalent attachment, these non-covalent interactions preserve the electronic conductivity of the Ti3C2 MXene nanosheets. Finally, the addition of MO-derived nitrogen (N) and sulfur (S) atoms to Ti3C2 MXene enhanced the electronegativity and improved its affinity for specific molecules, resulting in high-performance electrocatalytic activity. The proposed biosensor exhibited a wide linear response in concentration ranges of 0.01-0.3 µM and 0.5-120 µM, with a low detection limit of 15 nM for tryptophan detection, and high anti-interference ability in complex media of human urine and egg white matrices. The exceptional abilities of the MO/Ti3C2 nanocatalyst make it a promising electrode material for the detection of important biomolecules.
Subject(s)
Azo Compounds , Biosensing Techniques , Electrochemical Techniques , Limit of Detection , Nanocomposites , Titanium , Tryptophan , Tryptophan/chemistry , Tryptophan/urine , Tryptophan/analysis , Electrochemical Techniques/methods , Nanocomposites/chemistry , Titanium/chemistry , Biosensing Techniques/methods , Azo Compounds/chemistry , Humans , Oxidation-Reduction , Electrodes , PorosityABSTRACT
In this paper, a versatile heterogeneous nanocatalyst was fabricated employing a self-assembly technique. To commence, Fe3O4 MNPs were coated with a thin layer of SiO2 using the stobbers method. Subsequently, the surface was further functionalized with 3-CPMS, followed by a reaction with a Schiff base. Finally, nickel NPs were deposited on the surface through in situ deposition, forming the Fe3O4@SiO2@3-CPMS@L-Ni magnetic nanocatalyst. The architecture of this magnetic nanocatalyst was meticulously characterized through an array of sophisticated techniques: XRD, FT-IR, SEM, TEM, BET and VSM. The XRD diffraction pattern confirmed the presence of Fe3O4 MNPs, SiO2, and Ni peaks, providing evidence for successful synthesis. Moreover, the successful functionalization with a Schiff base was demonstrated by the presence of an azomethane peak in the FTIR spectra of the synthesized nanocatalyst. The fabricated nanocatalyst was adeptly utilized for the reduction of 4-NP, NB, and MO demonstrating a remarkably elevated rate of catalytic efficacy. Moreover, this catalyst was effortlessly retrievable through the application of an external magnet, and it maintained its catalytic prowess across at least six consecutive cycles. The utilization of water as an environmentally friendly solvent, coupled with the utilization of abundant and cost-effective nickel catalyst instead of the costly Pd or Pt catalysts, along with the successful recovery and scalability of the catalyst, render this method highly advantageous from both environmental and economic perspectives for the reduction of 4-NP, NB, and MO.
Subject(s)
Nickel , Silicon Dioxide , Nickel/chemistry , Catalysis , Silicon Dioxide/chemistry , Nitrobenzenes/chemistry , Nitrophenols/chemistry , Azo Compounds/chemistry , Spectroscopy, Fourier Transform InfraredABSTRACT
A novel and sensitive fluorescence ratiometric method is developed for urea detection based on the pH-sensitive response of two fluorescent carbon dot (CD) systems: R-CDs/methyl red (MR) and NIR-CDs/Cu2+. The sensing mechanism involves breaking down urea using the enzyme urease, releasing ammonia and increasing pH. At higher pH, the fluorescence of NIR-CDs is quenched due to the enhanced interaction with Cu2+, while the fluorescence of R-CDs is restored as the acidic MR converts to its basic form, removing the inner filter effect. The ratiometric signal (F608/F750) of the R-CDs/MR and NIR-CDs/Cu2+ intensities changed in response to the pH induced by urea hydrolysis, enabling selective and sensitive urea detection. Detailed spectroscopic and morphological investigations confirmed the fluorescence probe design and elucidated the sensing mechanism. The method exhibited excellent sensitivity (0.00028 mM LOD) and linearity range (0.001 - 8.0 mM) for urea detection, with successful application in milk samples for monitoring adulteration, demonstrating negligible interference and high recovery levels (96.5% to 101.0%). This ratiometric fluorescence approach offers a robust strategy for selective urea sensing in complicated matrices.
Subject(s)
Carbon , Copper , Fluorescent Dyes , Limit of Detection , Quantum Dots , Spectrometry, Fluorescence , Urea , Urease , Urea/analysis , Urea/chemistry , Urease/chemistry , Copper/chemistry , Carbon/chemistry , Hydrogen-Ion Concentration , Quantum Dots/chemistry , Fluorescent Dyes/chemistry , Spectrometry, Fluorescence/methods , Animals , Milk/chemistry , Azo Compounds/chemistry , Food Contamination/analysisABSTRACT
The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) has surged due to changes in economic and lifestyle patterns, leading to significant health challenges. Previous reports have studied the establishment of animal and cellular models for MASLD, highlighting differences between them. In this study, a cellular model was created by inducing fat accumulation in MASLD. HepG2 cells were stimulated with the unsaturated fatty acid oleic acid at various concentrations (0.125 mM, 0.25 mM, 0.5 mM, 1 mM) to emulate MASLD. The model's efficacy was assessed using cell counting kit-8 assays, Oil Red O staining, and lipid content analysis. This study aimed to create a simple-to-operate cellular model for MASLD cells. Results from the cell counting kit-8 assays showed that the survival of HepG2 cells was dependent on the concentration of oleic acid, with a GI50 of 1.875 mM. Cell viability in the 0.5 mM and 1 mM groups were significantly lower than those in the control group (P < 0.05). Furthermore, Oil Red O staining and lipid content analysis examined fat deposition at varying oleic acid concentrations (0.125 mM, 0.25 mM, 0.5 mM, 1 mM) on HepG2 cells. The lipid content of the 0.25 mM, 0.5 mM, and 1 mM groups was significantly higher than that of the control group (P < 0.05). Additionally, triglyceride levels in the OA groups were significantly higher than those in the control group (P < 0.05).
Subject(s)
Fatty Liver , Oleic Acid , Humans , Hep G2 Cells , Oleic Acid/pharmacology , Fatty Liver/metabolism , Fatty Liver/pathology , Azo Compounds , Lipid Metabolism/physiology , Models, BiologicalABSTRACT
Dye-decolorizing peroxidases (DyPs) belong to a novel superfamily of heme peroxidases that can oxidize recalcitrant compounds. In the current study, the GlDyP2 gene from Ganoderma lucidum was heterologously expressed in Escherichia coli, and the enzymatic properties of the recombinant GlDyP2 protein were investigated. The GlDyP2 protein could oxidize not only the typical peroxidase substrate ABTS but also two lignin substrates, namely guaiacol and 2,6-dimethoxy phenol (DMP). For the ABTS substrate, the optimum pH and temperature of GlDyP2 were 4.0 and 35 °C, respectively. The pH stability and thermal stability of GlDyP2 were also measured; the results showed that GlDyP2 could function normally in the acidic environment, with a T50 value of 51 °C. Moreover, compared to untreated controls, the activity of GlDyP2 was inhibited by 1.60 mM of Mg2+, Ni2+, Mn2+, and ethanol; 0.16 mM of Cu2+, Zn2+, methanol, isopropyl alcohol, and Na2EDTA·2H2O; and 0.016 mM of Fe2+ and SDS. The kinetic constants of recombinant GlDyP2 for oxidizing ABTS, Reactive Blue 19, guaiacol, and DMP were determined; the results showed that the recombination GlDyP2 exhibited the strongest affinity and the most remarkable catalytic efficiency towards guaiacol in the selected substrates. GlDyP2 also exhibited decolorization and detoxification capabilities towards several dyes, including Reactive Blue 19, Reactive Brilliant Blue X-BR, Reactive Black 5, Methyl Orange, Trypan Blue, and Malachite Green. In conclusion, GlDyP2 has good application potential for treating dye wastewater.
Subject(s)
Coloring Agents , Enzyme Stability , Escherichia coli , Guaiacol , Recombinant Proteins , Reishi , Temperature , Coloring Agents/metabolism , Coloring Agents/chemistry , Reishi/genetics , Reishi/enzymology , Reishi/metabolism , Hydrogen-Ion Concentration , Escherichia coli/genetics , Escherichia coli/metabolism , Recombinant Proteins/metabolism , Recombinant Proteins/genetics , Recombinant Proteins/chemistry , Guaiacol/metabolism , Guaiacol/analogs & derivatives , Biodegradation, Environmental , Kinetics , Benzothiazoles/metabolism , Substrate Specificity , Lignin/metabolism , Oxidation-Reduction , Peroxidase/genetics , Peroxidase/metabolism , Peroxidase/chemistry , Fungal Proteins/genetics , Fungal Proteins/metabolism , Fungal Proteins/chemistry , Peroxidases/genetics , Peroxidases/metabolism , Peroxidases/chemistry , Water Pollutants, Chemical/metabolism , Azo Compounds/metabolism , Wastewater/microbiology , Wastewater/chemistry , Sulfonic Acids/metabolism , Anthraquinones , Rosaniline DyesABSTRACT
The C-diazeniumdiolate (N-nitrosohydroxylamine) group in the amino acid graminine (Gra) is a newly discovered Fe(III) ligand in microbial siderophores. Graminine was first identified in the siderophore gramibactin, and since this discovery, other Gra-containing siderophores have been identified, including megapolibactins, plantaribactin, gladiobactin, trinickiabactin (gramibactin B), and tistrellabactins. The C-diazeniumdiolate is photoreactive in UV light which provides a convenient characterization tool for this type of siderophore. This report details the process of genomics-driven identification of bacteria producing Gra-containing siderophores based on selected biosynthetic enzymes, as well as bacterial culturing, isolation and characterization of the C-diazeniumdiolate siderophores containing Gra.
Subject(s)
Siderophores , Siderophores/chemistry , Siderophores/isolation & purification , Siderophores/metabolism , Azo Compounds/chemistry , Azo Compounds/metabolismABSTRACT
Azo dye-containing sewage is commonly detected at high salinity, temperature and pH. In this study, a halo-thermoalkalophilic azo dye decolorization consortium was enriched and named "consortium HL". Consortium HL which was dominated by Marinobacter (84.30%), Desulfocurvibacter (1.89%), and Pseudomonas (1.85%), was able to completely decolorize Direct Blue 5B (DB5) during incubation with the material at 5% salinity, 50 °C, and pH 9 for 30 h. The decolorization mechanism was proposed based on combined metagenomic analysis, GCâMS, and enzymatic activity detection. The action of the consortium HL showed great tolerance to variations in salinity, temperature and pH. A phytotoxicity study indicated that the metabolic intermediates showed no significant toxicity to the generation of Cucumis sativus and Oryza sativa seeds. This study, in which azo dye decolorization and degradation under high-salt, high-temperature and high-alkalinity conditions were investigated and deeply analyzed by metagenomic information, is the first report regarding the ability of Marinobacter to decolorize azo dyes at high temperatures.
Subject(s)
Biodegradation, Environmental , Marinobacter , Marinobacter/metabolism , Marinobacter/genetics , Azo Compounds/metabolism , Azo Compounds/chemistry , Coloring Agents/metabolism , Coloring Agents/chemistry , Microbial Consortia , Salinity , Sewage/microbiology , Hydrogen-Ion Concentration , Temperature , Water Pollutants, Chemical/metabolism , Water Pollutants, Chemical/analysis , OryzaABSTRACT
Spinal muscular atrophy (SMA) is a prevalent paediatric neuromuscular disorder characterised by muscle weakness and atrophy resulting from degeneration of spinal cord anterior horn α motor neurons. Gene therapy formulations exhibit varying benefits and limitations, driving the need for patient-friendly treatment options tailored to specific populations. The objective of this meta-analysis was to assess the effectiveness of gene therapy for motor function in children with SMA. The analysis encompassed a total of 719 participants from six randomised controlled trials (RCTs) conducted between 2017 and 2023. Among the studies, one demonstrated a significant and large standardised effect size (Cohen's d) favouring nusinersen in terms of Hammersmith Functional Motor Scale - Expanded (HFMSE) (d = 0.97) and revised upper limb module (RULM) (d = 0.96). Additionally, another study showed a moderate standardised effect size (Cohen's d) in favour of nusinersen concerning Hammersmith Infant Neurological Examination-Section 2 (HINE-2) (d = 0.48). However, it is important to note that further research with a longer duration of observation is required to strengthen the evidence. Key Words: Spinal muscular atrophy, Nusinersen, Risdiplam, Motor function, Cohen's d.
Subject(s)
Oligonucleotides , Spinal Muscular Atrophies of Childhood , Humans , Oligonucleotides/therapeutic use , Spinal Muscular Atrophies of Childhood/drug therapy , Spinal Muscular Atrophies of Childhood/physiopathology , Genetic Therapy , Treatment Outcome , Randomized Controlled Trials as Topic , Child , Azo Compounds , PyrimidinesABSTRACT
ConspectusLight is ubiquitously available to probe the structure and dynamics of biomolecules and biological tissues. Generally, this cannot be done directly with visible light, because of the absence of absorption by those biomolecules. This problem can be overcome by incorporating organic molecules (chromophores) that show an optical response in the vicinity of those biomolecules. Since those optical properties are strongly dependent on the chromophore's environment, time-resolved spectroscopic studies can provide a wealth of information on biosystems at the molecular scale in a nondestructive way. In this work, we give an overview on the multiscale computational strategy developed by us in the last eight years and prove that theoretical studies and simulations are needed to explain, guide, and predict observations in fluorescence experiments. As we challenge the accepted views on existing probes, we discover unexplored abilities that can discriminate surrounding lipid bilayers and their temperature-dependent as well as solvent-dependent properties. We focus on three archetypal chromophores: diphenylhexatriene (DPH), Laurdan, and azobenzene. Our method shows that conformational changes should not be neglected for the prototype rod-shaped molecule DPH. They determine its position and orientation in a liquid-ordered (Lo) sphingomyelin/cholesterol (SM/Chol) bilayer and are responsible for a strong differentiation of its absorption spectra and fluorescence decay times in dioleoylphosphatidylcholine (DOPC) and dipalmitoylphosphatidylcholine (DPPC) membranes, which are at room temperature in liquid-disordered (Ld) and solid-gel (So) phases, respectively. Thanks to its pronounced first excited state dipole moment, Laurdan has long been known as a solvatochromic probe. Since this molecule has however two conformers, we prove that they exhibit different properties in different lipid membrane phases. We see that the two conformers are only blocked in one phase but not in another. Supported by fluorescence anisotropy decay simulations, Laurdan can therefore be regarded as a molecular rotor. Finally, the conformational versatility of azobenzene in saturated Ld lipid bilayers is simulated, along with its photoisomerization pathways. By means of nonadiabatic QM/MM surface hopping analyses (QM/MM-SH), a dual mechanism is found with a torsional mechanism and a slow conversion for trans-to-cis. For cis-to-trans, simulations show a much higher quantum yield and a so-called "pedal-like" mechanism. The differences are related to the different potential energy surfaces as well as the interactions with the surrounding alkyl chains. When tails of increased length are attached to this probe, cis is pushed toward the polar surface, while trans is pulled toward the center of the membrane.
Subject(s)
Azo Compounds , Lipid Bilayers , Lipid Bilayers/chemistry , Azo Compounds/chemistry , Diphenylhexatriene/chemistry , 2-Naphthylamine/analogs & derivatives , 2-Naphthylamine/chemistry , Laurates/chemistry , Molecular Dynamics SimulationABSTRACT
Magnetic biochar (MBC) was obtained from pepper straw by impregnation-microwave pyrolysis method. The pyrolysis temperature and FeCl3 impregnation concentration were investigated on the structural properties of MBC and the adsorption of methyl orange (MO) in water. Characterization results showed that pyrolysis temperature and iron species significantly increased the specific surface area of MBC, which could reach the maximum of 2038.61 m2/g, and also provided more active adsorption sites by promoting the generation of graphitized structures and surface polar functional groups. MBC0.2-900 was selected as the adsorbent for MO with the maximum adsorption capacity reached 437.18 mg·g-1, 3.4 times higher than the virgin biochar. The adsorption process was dominated by chemisorption as well as spontaneous and exothermic. The adsorption mechanisms included pore-filling interaction, π-π EDA interaction, electrostatic interaction, hydrogen bonding, and Lewis acid-base electron interaction. In addition, MBC also exhibited excellent separability and reusability as a low-cost adsorbent. This study provided some theoretical foundation and technological support for producing high-performance biochar and developing pollutant removal technology in wastewater.
Subject(s)
Azo Compounds , Charcoal , Water Pollutants, Chemical , Water Purification , Charcoal/chemistry , Adsorption , Azo Compounds/chemistry , Azo Compounds/isolation & purification , Water Pollutants, Chemical/chemistry , Water Pollutants, Chemical/isolation & purification , Water Purification/methods , KineticsABSTRACT
Dyes are the coloured substances that are applied on different substrates such as textiles, leather and paper products, etc. Azo dyes release from the industries are toxic and recalcitrant wastewater pollutants, therefore it is necessary to degrade these pollutants from water. In this study, the palladium (0) nanoparticles (PdNPs) were generated through the biological process and exhibited for the catalytic degradation of azo dye. The palladium nanoparticles (PdNPs) were synthesized by using the cell-free approach i.e. extract of fungal strain Rhizopus sp. (SG-01), which significantly degrade the azo dye (methyl orange). The amount of catalyst was optimized by varying the concentration of PdNPs (1 mg/mL to 4 mg/mL) for 10 mL of 50 ppm methyl orange (MO) dye separately. The time dependent study demonstrates the biogenic PdNPs could effectively degrade the methyl orange dye up to 98.7% with minimum concentration (3 mg/mL) of PdNPs within 24 h of reaction. The long-term stability and effective catalytic potential up to five repeated cycles of biogenic PdNPs have good significance for acceleration the degradation of azo dyes. Thus, the use of biogenic palladium nanoparticles for dye degradation as outlined in the present study can provide an alternative and economical method for the synthesis of PdNPs as well as degradation of azo dyes present in wastewater and is helpful to efficiently remediate textile effluent.
Subject(s)
Azo Compounds , Biodegradation, Environmental , Coloring Agents , Palladium , Rhizopus , Wastewater , Water Pollutants, Chemical , Azo Compounds/metabolism , Azo Compounds/chemistry , Palladium/chemistry , Palladium/metabolism , Coloring Agents/metabolism , Coloring Agents/chemistry , Catalysis , Water Pollutants, Chemical/metabolism , Wastewater/chemistry , Wastewater/microbiology , Rhizopus/metabolism , Metal Nanoparticles/chemistryABSTRACT
The presented study was focused on the simple, eco-friendly synthesis of composite hydrogels of crosslinked carboxymethyl cellulose (CMC)/alginate (SA) with encapsulated g-C3N4 nanoparticles. The structural, textural, morphological, optical, and mechanical properties were determined using different methods. The encapsulation of g-C3N4 into CMC/SA copolymer resulted in the formation of composite hydrogels with a coherent structure, enhanced porosity, excellent photostability, and good adhesion. The ability of composite hydrogels to eliminate structurally different dyes with the same or opposite charge properties (cationic Methylene Blue and anionic Orange G and Remazol Brilliant Blue R) in both single- and binary-dye systems was examined through adsorption and photocatalytic reactions. The interactions between the dyes and g-C3N4 and the negatively charged CMC/SA copolymers had a notable influence on both the adsorption capacity and photodegradation efficiency of the prepared composites. Scavenger studies and leaching tests were conducted to gain insights into the primary reactive species and to assess the stability and long-term performance of the g-C3N4/CMC/SA beads. The commendable photocatalytic activity and excellent recyclability, coupled with the elimination of costly catalyst separation requirements, render the g-C3N4/CMC/SA composite hydrogels cost-effective and environmentally friendly materials, and strongly support their selection for tackling environmental pollution issues.
Subject(s)
Alginates , Carboxymethylcellulose Sodium , Coloring Agents , Hydrogels , Water Pollutants, Chemical , Carboxymethylcellulose Sodium/chemistry , Hydrogels/chemistry , Alginates/chemistry , Coloring Agents/chemistry , Catalysis , Water Pollutants, Chemical/chemistry , Methylene Blue/chemistry , Azo Compounds/chemistry , Nitriles/chemistry , Nitrogen Compounds/chemistry , Photolysis , Adsorption , Green Chemistry Technology/methods , Anthraquinones , GraphiteABSTRACT
Water pollution and antimicrobial resistance (AMR) have become two global threats; 80% of diseases and 50% of child deaths are due to poor water quality. In this study, hydrothermal processing was employed to manufacture manganese oxide nanorods. Silver dopant was deposited on the surface of manganese oxide. XRD diffractogram confirmed the facile synthesis of Ag/Mn2O3 nanocomposite. XPS survey analysis demonstrated silver content of 9.43 atom %. Photocatalytic measurements demonstrated the outstanding efficiency of the Ag-Mn2O3 compared to virgin oxide particles under visible radiation. Degradation efficiencies Mn2O3 and Ag/Mn2O3 on methyl orange (MO) dye was found to be 53% and 85% under visible spectrum. Silver dopant was found to decrease the binding energy of valence electrons; this action could support electron-hole pair generation under visible spectrum and could promote catalytic performance. Ag/Mn2O3 NPs demonstrated most effective performance (95% removal efficiency) at pH 3; this could be ascribed to the electrostatic attraction between positively charged catalyst and the negatively charged MO. Ag/Mn2O3 demonstrated enhanced antibacterial activity against Gram-positive Staphylococcus aureus (S. aureus) (19 mm ZOI), and Gram-negative Escherichia coli (E. coli) (22 mm ZOI) respectively; the developed nanocomposite demonstrated advanced anti-film activity with inhibition percentage of 95.5% against E. coli followed by 89.5% against S. aureus.
Subject(s)
Escherichia coli , Manganese Compounds , Nanocomposites , Oxides , Silver , Staphylococcus aureus , Manganese Compounds/chemistry , Manganese Compounds/pharmacology , Oxides/chemistry , Oxides/pharmacology , Silver/chemistry , Silver/pharmacology , Nanocomposites/chemistry , Catalysis , Escherichia coli/drug effects , Staphylococcus aureus/drug effects , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/chemical synthesis , Light , Azo Compounds/chemistry , Azo Compounds/pharmacology , Microbial Sensitivity Tests , Anti-Infective Agents/pharmacology , Anti-Infective Agents/chemistry , Anti-Infective Agents/chemical synthesis , Photochemical ProcessesABSTRACT
A novel bio-carrier, PVA/Fe/starch gel bead, was fabricated and developed to enhance the anaerobic treatment performance of synthetic azo dye-containing wastewater. PVA-gel beads with 5 % magnetite and 0.5 % starch were optimal for physical strength and treatment performance. A pair of 2 L-up-flow anaerobic sludge blankets (UASB), one with the bead (UB) and another without (U) as a controller, operated continuously at 30 °C and an HRT of 11-24 h for 302 days. UB showed better performance than U in most phases, especially with influent dye of 200 mg·L-1, suggesting a greater tolerance to dye toxicity of UB than U. Microbial analysis revealed that the PVA/Fe/starch gel beads successfully captured the dye degrader Clostridium. Diversity indices indicated that PVA/Fe/Starch gel beads effectively support microbial diversity and resilience under varying dye concentrations. Overall, these findings demonstrate the potential of PVA/Fe/Starch gel beads to improve the stability and efficiency of the dye treatment system.
Subject(s)
Azo Compounds , Bioreactors , Coloring Agents , Polyvinyl Alcohol , Starch , Starch/chemistry , Coloring Agents/chemistry , Polyvinyl Alcohol/chemistry , Azo Compounds/chemistry , Anaerobiosis , Gels/chemistry , Iron/chemistry , Water Purification/methods , Sewage/microbiology , Biodegradation, EnvironmentalABSTRACT
Herein, the surface-enhanced Raman scattering (SERS) platform was combined with an azo coupling reaction and an aluminum alloy covered with a hydrophobic layer of praseodymium oxide and stearic acid complexes for the detection of histamine. The praseodymium oxide on aluminum alloy was successfully synthesized by the rare-earth-salt-solution boiling bath method and modified by stearic acid. Its surface exhibits a water contact angle (WCA) of 125.0°. Through the azo derivatization reaction with 3-amino-5-mercapto-1,2,4-triazole (AMTA) diazonium salts, histamine can be converted into the derivatization product with higher Raman activity. The mixture of the derivatization product and ß-cyclodextrin-modified Ag nanoparticles (ß-CD-AgNPs) were dropped onto the surface of an aluminum alloy covered with a hydrophobic layer of praseodymium oxide and stearic acid complexes, and dried for SERS measurement. The intensity ratio between the SERS peaks at 1246 cm-1 and 1104 cm-1 (I1246/I1104) of the derivatization product was used for the quantification of histamine. Under the selected conditions, the limit of detection (LOD) and the limit of quantification (LOQ) for this method were 7.2 nM (S/N = 3) and 24 nM (S/N = 10), respectively. The relative standard deviation (RSD) of this method for the determination of 1 µM histamine was 6.1 % (n = 20). The method was also successfully used for the determination of histamine in fish samples with recoveries ranging from 92 % to 111 %. The present method is simple, sensitive, reliable, and may provide a new approach for preparing the composite hydrophobic layer that can enhance SERS signals through hydrophobic condensation effect. Meanwhile, it may have a promising future in the determination of small molecular compounds containing an imidazole ring.
Subject(s)
Histamine , Hydrophobic and Hydrophilic Interactions , Metal Nanoparticles , Silver , Spectrum Analysis, Raman , Spectrum Analysis, Raman/methods , Histamine/analysis , Histamine/chemistry , Silver/chemistry , Metal Nanoparticles/chemistry , Limit of Detection , Azo Compounds/chemistry , Stearic Acids/chemistry , Animals , Fishes , Surface PropertiesABSTRACT
The bicarbonate-activated hydrogen peroxide (BAP) system is widely studied for organic pollutant degradation in wastewater treatment. Ca2Co2O5, a heterogeneous catalyst containing multivalent cobalt including Co(II) and Co(III), was herein investigated as a BAP activator, and Acid Orange 7 (AO7) was used as a model pollutant. Ca2Co2O5 exhibited good activation performance. The degradation rate and the initial rate constant of the Ca2Co2O5-activated BAP system were 5.4 and 11.2 times as high as the BAP system, respectively. The removal rate of AO7 reached 90.9% in 30 min under optimal conditions (AO7 20 mg/L, Ca2Co2O5 0.2 g/L, H2O2 1 mM, NaHCO3 5 mM, pH 8.5, 25â). The Ca2Co2O5 catalyst exhibited good stability and recyclability, retaining 85% of AO7 removal rate in the fifth run. Compared to the BAP system, a lower dosage of H2O2 was required and a higher initial concentration of pollutants allowed for effective degradation in the Ca2Co2O5-BAP system. X-ray photoelectron spectroscopy was used to analyze the catalytic mechanism. The analysis showed that the good catalytic performance of Ca2Co2O5 attributes to its high proportion of oxygen vacancies and Co(III) species, and the presence of Ca. The active species O2â¢-, â¢OH, and 1O2 are responsible for the degradation, as indicated by the quenching experiments. The degradation mechanism of AO7 was speculated based on UV-Vis spectral analysis and the identification of degradation intermediates. The azo form, naphthalene and benzoic rings in the AO7 structure are destroyed in the decomposition. This research provides a feasible approach to designing effective and reusable BAP activators for pollutant degradation in wastewater treatment.
Subject(s)
Hydrogen Peroxide , Water Pollutants, Chemical , Hydrogen Peroxide/chemistry , Water Pollutants, Chemical/chemistry , Cobalt/chemistry , Bicarbonates/chemistry , Catalysis , Wastewater/chemistry , Azo Compounds , BenzenesulfonatesABSTRACT
Hypoxia is known as a specific signal of various diseases, such as liver fibrosis. We designed a hypoxia-sensitive fluorometric approach that cleaved the azo bond (NâN) in the presence of hypoxia-controlled agents (sodium dithionite and azoreductase). 4-(2-Pyridylazo) resorcinol (Py-NâN-RC) bears a desirable hypoxia-responsive linker (NâN), and its azo bond breakup can only occur in the presence of sodium dithionite and azoreductase and leads to the release of 2,4-dihydroxyaniline, which can react with 3-[2-(2-aminoethylamino)ethylamino]propyltrimethoxysilane to generate yellow fluorescent silicon nanoparticles. This approach exhibited high selectivity and sensitivity toward both sodium dithionite and azoreductase over other potential interferences. The mouse liver microsome, which is known to contain azoreductase, was applied and confirmed the feasibility of the designed platform. Py-NâN-RC is expected to be a practical substrate for hypoxia-related biological analyses. Furthermore, silicon nanoparticles were successfully applied for Hela cell imaging owing to their negligible cytotoxicity and superb biocompatibility.
Subject(s)
Azo Compounds , Nanoparticles , Silicon , Silicon/chemistry , Humans , Nanoparticles/chemistry , HeLa Cells , Azo Compounds/chemistry , Animals , Mice , Resorcinols/chemistry , Hypoxia/metabolism , Cell Hypoxia , Molecular Structure , Nitroreductases/metabolismABSTRACT
The current study was conducted to understand the sole role of graphite as a substrate material in a dual-chambered baffled electroactive wetland (EW) in the treatment of Methyl red dye-containing wastewater. The results obtained were compared with conventional gravel-based unplanted dual-chambered constructed wetlands (CW) at a lab scale. The highest dye decolorisation and COD removal efficiency achieved was 92.88 ± 1.6% and 95.78 ± 4.1%, respectively, in the electro-active wetland. Dissolved oxygen (DO) and pH conditions were appropriately maintained in both the microcosms because of separated aerobic and anaerobic chambers. UV-vis and gas chromatography-mass spectroscopy analysis revealed the production of by-products like 4-amino benzoic and N- N dimethyl phenyl-diamine of MR in microcosms and revealed further mineralisation of by-products in the aerobic zone of electroactive-wetland. Higher root growth of Cicer aerietinum and Vigna radiata was observed in the presence of effluents of baffled electroactive wetlands compared to constructed wetland, indicating a decrease in phytotoxicity. Metagenomic analysis revealed the abundance of potential microbes for MR and organic matter removal from phylum Proteobacteria, Firmicutes, Bacteroidetes, and Euryarchaeota. A batch adsorption study revealed a higher adsorption capability of graphite material in comparison to gravel. Hence, this study demonstrated that graphite is an appropriate substrate in electroactive wetland in facilitating microbial attachments and enhancing dye degradation, in addition to exhibiting superior adsorption quality.
Subject(s)
Azo Compounds , Coloring Agents , Graphite , Waste Disposal, Fluid , Wastewater , Wetlands , Wastewater/chemistry , Graphite/chemistry , Waste Disposal, Fluid/methods , Water Pollutants, ChemicalABSTRACT
In this work, we delve into the impact of photoisomerization of photoswitchable lipids (PSLs) on the membrane structure and dynamics at a molecular level. Through all-atom molecular dynamics simulations, we explore how UV irradiation-induced trans-to-cis isomerization of these lipids, particularly the azobenzene-derivatized phosphatidylcholine (AzoPC) lipid, influences the structure and dynamics of a simplified lipid membrane, mimicking those of E. coli bacteria across different temperatures. Our findings align with previous experimental observations regarding membrane properties and offer insights into localized effects and microscopic heterogeneity. Additionally, we estimate the relaxation time scale of the lipid membrane following AzoPC photoisomerization. Moreover, we demonstrate the feasibility of photoactivated drug release, exemplified by the controlled liberation of doxorubicin, an anticancer agent, through the membrane, suggesting the potential of PSLs in engineering photoactivated liposomes, coined as photoazosomes, for precise targeted drug delivery applications.