Search Results (140)

Nonsteroidal anti-inflammatory drugs such as phenylbutazone (PBZ) are among the most widely used medications globally due to their effectiveness in relieving pain and reducing inflammation. This study aims to detect PBZ with metallic particle-based electrochemical sensors using cyclic voltammetry (CV) in the presence of catechol as a redox probe. The approach focuses on evaluating the electrochemical behaviour of PBZ under different experimental conditions and optimizing the detection parameters to develop a simple, rapid, and cost-effective analytical method suitable for this pharmaceutical compound in lab practice. CV was performed using four types of screen-printed electrodes, each modified with different transitional metal particles, in potassium ferrocyanide/potassium ferricyanide, catechol, and catechol-PBZ solutions to study the electrochemical response and detection capability for PBZ. The best performance characteristics were obtained for the sensor modified with Ir particles that detect PBZ, with a linearity range of 0.01 to 1.00 μM and a detection limit of 1.53 nM. Additionally, Fourier-transform infrared spectroscopy (FT-IR) was used to characterize the PBZ in pharmaceuticals. The method using an iridium-modified sensor developed in this study allows the accurate detection of PBZ in pharmaceuticals with a relative error lower than 4%. Full article

Our recent work has focused on red light-mediated photoreduction of p-benzoquinones and both o-, and p-naphthoquinones using methylene blue and the chlorophyll metabolite, pheophorbide A as photosensitizers. Photoreduction of biologically relevant quinones mimics photoreduction of plastoquinone by chlorophyll in photosynthesis. We examined photo-oxidation and photoreduction reactions of catechols because their oxidation to o-quinones by reactive oxygen species is implicated in protein damage in neurodegeneration. Photo-oxidation of catecholamines including dopamine, epinephrine and norepinephrine required red light, methylene blue or pheophorbide A, and molecular oxygen. Their cyclized oxidation products, aminochrome, adrenochrome and noradrenochrome, were detected by UV/visible spectroscopy. Hydrogen peroxide was generated during photo-oxidation by singlet oxygen-dependent oxidation of catecholamines. Inclusion of tertiary amine electron donors decreased cyclized products but did not affect hydrogen peroxide yield consistent with concurrent photo-oxidation followed by photoreduction of the o-quinone intermediate. Unreacted dopamine and norepinephrine were quantified using 3-hydroxyphenyl boronic acid following photochemical reactions. Dopamine and norepinephrine boronate esters absorb at 417 and 550 nm. Photo-oxidation of dihydroxycaffeic acid and dihydroxyphenyl acetic acid was also evaluated by detecting their boronate esters at 475 nm. We hypothesize that photoreduction of transient o-quinones by the combination of red light and dietary chlorophyll metabolites may be a path to limit protein damage and to recycle catechol antioxidants. Full article

Idesia polycarpa is a multipurpose tree species valued for both fruit production and timber and is often referred to as a “beautiful oil reservoir on trees”. However, research has largely focused on fruits, whereas the metabolic composition and potential value of other tissues, such as leaves and shoot tips, remain insufficiently characterized. Here, we employed UPLC–MS/MS-based untargeted metabolomics to compare metabolite profiles and functional components between the leaves and shoot tips of I. polycarpa. In total, 378 differential metabolites were identified, with 105 significantly upregulated in leaves and 273 significantly upregulated in shoot tips. Among these, 32 metabolites were detected exclusively in shoot tips, and 22 were unique to leaves. Leaves were enriched in secondary metabolites, particularly flavonoids and phenolic acids, with scutellarin and catechol as representative compounds. In contrast, shoot tips exhibited higher levels of primary metabolites, including nucleotides and their derivatives as well as amino acids, with catechin and epicatechin being representative compounds. In addition, targeted metabolomics was performed to quantify 53 flavonoids in leaves; scutellarin (2088.1350 μg/g) and apigenin-7-O-glucuronide (1020.9085 μg/g) showed the highest concentrations. Collectively, these results reveal tissue-specific metabolic characteristics in I. polycarpa and provide a data basis for future functional studies and the comprehensive utilization of leaves and shoot tips. Full article

This study presents a straightforward process for producing a hybrid ternary composite of silver nanoparticles (Ag NPs), small graphene oxide (s-GO), and zirconia (ZrO₂) and its use as an electrode material for electrochemical sensing. The physico-chemical properties of the ternary composite were analyzed by means of field emission scanning electron microscopy (FE-SEM), ultraviolet-visible (UV-vis) and FTIR spectroscopy, X-ray Photoelectron Spectrometry (XPS) and contact angle (CA) measurements. The synthesized hybrid nanomaterial was employed as an electrode modifier in the fabrication of a modified screen-printed carbon electrode (SPCE) and used for the simultaneous electrochemical sensing of key environmental pollutants such as hydroquinone (HQ) and catechol (CAT). The developed sensor exhibited linearity in the range of 0–100 µM for both HQ and CAT, with sensitivity values of 2640 µA·mM⁻¹·cm⁻² for HQ and 5120 µA·mM⁻¹·cm⁻² for CAT. The limits of detection (LOD) were 1.5 µM for HQ and 0.72 µM for CAT, respectively. The synergistic enhancement of electron transfer kinetics, the increased electroactive surface area, the strong anti-interference capability, and excellent reproducibility and stability establish these modified electrodes as promising candidates for environmental monitoring and real sample analysis. Full article

Additive manufacturing, particularly fused deposition modeling (FDM), has emerged as a promising approach for producing electrochemical sensors based on conductive thermoplastic composites. In this study, the effects of various printing parameters (extrusion temperature, layer height and width, printing speed, and the number of conductive layers) on the electrochemical performance of PLA/CB electrodes fabricated via FDM were investigated. Electrochemical impedance spectroscopy analyses showed that properly adjusting these parameters promoted the formation of more efficient conductive pathways and reduced charge transfer resistance during monitoring of the redox behavior of the potassium ferrocyanide/ferricyanide probe. Furthermore, the electrochemical performance of the device was demonstrated through the detection of different model analytes, including dopamine, catechol, hydroquinone, paracetamol, and uric acid. The device was also applied to the determination of dopamine, achieving a detection limit of 0.16 µmol L⁻¹. Overall, the results highlighted that optimizing printing conditions is essential for improving the electrochemical performance of 3D-printed devices, reinforcing the potential of 3D printing as a promising route for the fabrication of electrodes for electroanalytical applications. Full article

Reactive oxygen species (ROS) are well-known as major contributors to skin aging, and the application of antioxidants to suppress ROS has been increasingly emphasized in the field of cosmetics. Traditionally, plant-derived or synthetic antioxidants have been predominantly used. More recently, antioxidant, anti-aging, and anti-inflammatory effects of mussel extracts or mussel-derived hydrolysates have also been explored and proposed for cosmetic applications. However, there is still a lack of scientific research on the antioxidant and anti-aging effects of specific mussel foot proteins, particularly engineered recombinant proteins such as NGT-M001 (hybrid fp-151). Natural mussel adhesive proteins are characterized by an amino acid composition rich in tyrosine and catechol groups such as DOPA, which are believed to possess potent antioxidant activity. In this study, we quantitatively evaluated the antioxidant and anti-aging properties of a recombinant mussel adhesive protein (rMAP) lacking DOPA modification, and a rationally designed protein, NGT-M001. Antioxidant activity was assessed using ABTS and DPPH radical scavenging assays, while anti-aging potential was evaluated through collagenase and hyaluronidase inhibition assays. In the ABTS assay, the antioxidant capacity per molar unit of NGT-M001 was 27.76-fold higher than that of Trolox. NGT-M002 (pvFP-5), NGT-M003 (pvFP-5 fragment) and NGT-M004 (FP-1 fragment) exhibited 9.08-fold, 2.84-fold, and 8.54-fold higher activities, respectively. In the DPPH assay, NGT-M001 and NGT-M004 were not detected, whereas NGT-M002 and NGT-M003 showed 3.45-fold and 1.59-fold higher activity than Trolox, respectively. These findings suggest that recombinant mussel adhesive proteins such as NGT-M001 exhibit antioxidant activity and may serve as promising next-generation bioactive ingredients for functional medicine and cosmetic applications to improve skin health and radical scavenging. Full article

The increasing frequency, duration, and intensity of wildfires over the past decade have raised significant concerns about widespread exposure to wildfire smoke. Inhalation of wildfire smoke poses a substantial risk to human health, with epidemiological studies linking exposure to cardiovascular, respiratory, and neurological dysfunction. Wildfire smoke contains hundreds of chemical compounds across diverse classes, with concentrations varying by fuel type and combustion conditions. Phenolic compounds are prominent constituents of wood smoke, and catechol is especially abundant under smoldering conditions that produce dense smoke. In this study, ¹⁴C-labeled catechol was spiked into smoldering eucalyptus wood smoke extract (WSE) and administered to rats via intranasal instillation. Plasma was collected at 5 min and 2 h post-exposure. Samples were analyzed using parallel accelerator and molecular mass spectrometry (PAMMS). Major catechol-derived metabolites identified included benzene oxide, catechol-cysteine conjugate, and catechol-glutamine conjugate; the parent compound was not detected. These results indicate that inhaled catechol in wood smoke is quickly metabolized upon entry into circulation. PAMMS enabled both identification and relative quantification of circulating catechol metabolites, demonstrating feasibility for biomarker discovery and exposure assessment. Full article

This study explores a hybrid advanced electrochemical oxidation process (EAOP) intensified by solar irradiation and ozone for the treatment of wastewater containing COVID-19-related pharmaceuticals. Pilot-scale trials were performed in a 30 L compound parabolic collector (CPC)-type photoreactor with a boron-doped diamond (BDD–BDD) electrode configuration. Under optimal conditions (50 mg L⁻¹ paracetamol, 0.05 M Na₂SO₄, 0.50 mM Fe²⁺, pH 3.0, and 60 mA cm⁻²), the solar photoelectro-Fenton (SPEF) process achieved 78% chemical oxygen demand (COD) reduction within 90 min, with catechol and phenol detected as the main aromatic intermediates. When applied to a four-drug mixture (dexamethasone, paracetamol, amoxicillin, and azithromycin), the solar photoelectro-Fenton (SPEF–ozone (O₃)) system reached 60% degradation and 41% COD removal under solar conditions. The results highlight the synergistic effect of ozone and solar energy in enhancing the electrochemical oxidation process (EAOP) performance and demonstrate the potential of these processes for scalable and sustainable removal of pharmaceutical contaminants from wastewater. Full article

Given the significance of safeners and their potential to emit harmful substances into the environment, it is essential to develop suitable analytical methods for detecting these compounds. This study presents a molecularly imprinted electrochemical sensor designed for the sensitive and rapid detection of fenclorim (FM), a type of safener. Titanium carbide nanomaterials (Ti₃C₂T_x) were electrochemically deposited onto the glassy carbon electrode (GCE) to enhance electron transfer. Subsequently, molecularly imprinted polymers were fabricated through the electropolymerization of catechol in the presence of FM. The electrochemical behavior of each modified electrode was investigated using differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). Under optimized experimental conditions, the MIP/Ti₃C₂T_x/GCE sensor demonstrated a linear relationship with FM concentration ranging from 5 to 300 nM, with a limit of detection (LOD) of 1.56 nM (S/N = 3). Additionally, the sensor demonstrated excellent selectivity, stability, and reproducibility for FM detection and was successfully utilized for quantifying FM in real water samples. Full article

Nickel-based metal–organic frameworks (Ni-MOFs) have received enormous amounts of attention from the scientific community due to their excellent porosity, larger specific surface area, tunable structure, and intrinsic redox properties. In previous years, Ni-MOFs and their hybrid composite materials have been extensively explored for electrochemical sensing applications. As per the reported literature, Ni-MOF-based hybrid materials have been used in the fabrication of electrochemical sensors for the monitoring of ascorbic acid, glucose, L-tryptophan, bisphenol A, carbendazim, catechol, hydroquinone, 4-chlorophenol, uric acid, kaempferol, adenine, _L-cysteine, etc. The presence of synergistic effects in Ni-MOF-based hybrid materials plays a crucial role in the development of highly selective electrochemical sensors. Thus, Ni-MOF-based materials exhibited enhanced sensitivity and selectivity with reasonable real sample recovery, which suggested their potential for practical applications. In addition, Ni-MOF-based hybrid composites were also adopted as electrode modifiers for the development of supercapacitors. The Ni-MOF-based materials demonstrated excellent specific capacitance at low current densities with reasonable cyclic stability. This review article provides an overview of recent advancements in the utilization of Ni-MOF-based electrode modifiers with metal oxides, carbon-based materials, MXenes, polymers, and LDH, etc., for the electrochemical detection of environmental pollutants and biomolecules and for supercapacitor applications. In addition, Ni-based bimetallic and trimetallic catalysts and their composites have been reviewed for electrochemical sensing and supercapacitor applications. The key challenges, limitations, and future perspectives of Ni-MOF-based materials are discussed. We believe that the present review article may be beneficial for the scientific community working on the development of Ni-MOF-based materials for electrochemical sensing and supercapacitor applications. Full article

Vitamins are crucial micro-nutrients for overall well-being, making continuous monitoring essential. There are demands to provide an alternative detection, especially using a portable detection or a point-of-care-testing (POCT) device. One promising approach is employing an in situ electro-polymerised MIP (eMIP), which offers a straightforward polymerisation technique on screen-printed electrodes (SPEs). Here, we report a review based on three databases (PubMed, Scopus, and Web of Science) from 2014 to 2024 using medical subject heading (MeSH) terms “electrochemical polymerisation” OR “electropolymerisation” crossed with the terms “molecularly imprinted polymer” AND “vitamin A” OR “vitamin D” OR “vitamin E” OR “vitamin K” OR “fat soluble vitamin” OR “vitamin B” OR “vitamin C” OR “water soluble vitamin”. The resulting 12 articles covered the detection of vitamins in ascorbic acid, riboflavin, cholecalciferol, calcifediol, and menadione using monomers of catechol (CAT), 3,4-ethylenedioxythiophene (EDOT), o-aminophenol (oAP), o-phenylenediamine (oPD), pyrrole, p-aminophenol (pAP), p-phenylenediamine (pPD), or resorcinol (RES), using common bare electrodes including graphite rod electrode (GRE), glassy carbon electrode (GCE), gold electrode (GE), and screen-printed carbon electrode (SPCE). The most common electrochemical detections were differential pulse voltammetry (DPV) and linear sweep voltammetry (LSV). The imprinting factor (IF) of the eMIP-modified electrodes were from 1.6 to 21.0, whereas the cross-reactivity was from 0.0% to 29.9%. Several types of food and biological samples were tested, such as supplement tablets, poultry and pharmaceutical drugs, soft drinks, beverages, milk, infant formula, human and calf serum, and human plasma. However, more discoveries and development of detection methods needs to be performed, especially for the vitamins that have not been studied yet. This will allow the improvement in the application of eMIPs on portable-based detection and POCT devices. Full article

We demonstrate a rapid and sensitive boron detection method through current amplification mediated by supramolecular interaction. Oxidation peak currents obtained by cyclic voltammetry (CV) measurements of a ferrocene/catechol-functionalized β-cyclodextrin inclusion complex were amplified through an EC’ reaction (where EC’ denotes an electrochemical step followed by a catalytic chemical step). However, the amplified current was decreased by boric acid (the primary form of boron in water) addition at pH 8.6 owing to interactions of boron with the cis-diol structure of dihydroxybenzoic acid-β-cyclodextrin and ferrocene for ester formation. We determined the optimum CyD functionalization sites and measurement conditions and obtained a limit of detection of 0.16 mg B L⁻¹ for ferrocene/3,4-dihydroxybenzoic acid-β-cyclodextrin (Fc/3,4-DHBA-β-CyD). The binding constant (assuming a 1:1 binding model) for the interaction between Fc/3,4-DHBA-β-CyD and boric acid was estimated to be approximately 1500 M⁻¹. Boron concentrations in spiked real samples showed good recoveries and linear calibration curves. The electrochemical response of this system was not significantly affected by the presence of other anions or cations. We also found that an aqueous solution of 3,4-DHBA-β-CyD remained stable for at least 112 days. Full article

The complex nature of the hydrothermal liquefaction (HTL) of lignin product downstream requires an effective separation strategy. In this study, the use of adsorption separation was undertaken using deep eutectic solvent (DES)-modified amberlite XAD-4 adsorbents to achieve this goal. XAD-4 was modified with a choline chloride: ethylene glycol DES and characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and the Brunauer–Emmett–Teller (BET) test. In addition, the HTL product was characterized using Gas Chromatography with Flame Ionization Detection (GC-FID). The performance of unmodified and DES-modified adsorbents was initially tested on the model compounds of guaiacol, phenol and catechol, followed by the HTL product in a batch adsorption system. The Freundlich model best described the model compound adsorption system with a preferential affinity for guaiacol (k_f = 12.52), outperforming phenol and catechol. Adsorption experiments showed an increase in capacity and selectivity for all species when the DES-modified adsorbents were used at all mass loadings. GC-FID analytics showed the DES-modified XAD-4 (300 mg) as having the highest selectivity for guaiacol, with an equilibrium concentration of 121.45 mg/L representing an 85.25% uptake, while catechol was the least favorably adsorbed. These results demonstrate the potential of DES-functionalized XAD-4 adsorbents in selectively isolating high-value aromatics from the HTL of the lignin product stream. Full article

3,4-Dihydroxy-L-phenylalanine (DOPA) is a promising noncanonical amino acid (ncAA) that introduces novel catechol chemical features into proteins, expanding their functional potential. However, the most common approach to incorporating ncAAs into proteins relies on stop codon suppression, which is often limited by the competition of endogenous translational termination machinery. Here, we employed a special in vitro protein expression system that facilitates the efficiency of DOPA incorporation into proteins by removing essential Class I peptide release factors through targeted degradation. In the absence of both RF1 and RF2, we successfully demonstrated DOPA incorporation at all three stop codons (TAG, TAA, and TGA). By optimizing the concentration of engineered DOPA-specific aminoacyl-tRNA synthetase (DOPARS), DOPA, and DNA template, we achieved a synthesis yield of 2.24 µg of sfGFP with 100% DOPA incorporation in a 20 μL reaction system. DOPARS exhibited a dissociation constant (Kd) of 11.7 μM for DOPA but showed no detectable binding to its native counterpart, tyrosine. Additionally, DOPA was successfully incorporated into a reverse transcriptase, which interfered with its activity. This system demonstrates a fast and efficient approach for precise DOPA incorporation into proteins, paving the way for advanced protein engineering applications. Full article

Volatile organic compound pollution caused by toluene has become a global issue. In order to solve this problem, biodegradation of toluene has been applied all over the world. This study investigated the effects of Fe³⁺ on toluene degradation by the Rhodococcus sp. TG-1. The results show that 1 mg L⁻¹ Fe³⁺ increased the degradation rate of 600 mg L⁻¹ toluene from 61.9% to 87.2% at 16 h. The acceleration mechanism of Fe³⁺ was explicated using transmission electron microscope (TEM) and energy-dispersive X-ray spectroscopy (EDX) analyses, coupled plasma optical emission spectroscopy, an enzyme activity assay, and transcriptome analysis. Four genes were detected to be significantly up-regulated under Fe³⁺ induction, suggesting that Fe³⁺ might be implicated in toluene degradation. Meanwhile, Fe³⁺ was a component of the active center of catechol 1,2-dioxygenase (C12O) and significantly improved the enzyme activity of C12O. The mechanism by which Fe³⁺ accelerates toluene degradation was proposed based on the transcription levels of degradation genes and the enzyme activity of C12O. This study provided an improved method for enhancing the degradation effect of toluene and furthered our comprehension of the mechanism of toluene degradation. Full article