An efficient CuZr-based metallic glasses electrode material for electrocatalytic degradation of azo dyes.

Metallic glasses have received a lot of attention on wastewater treatment due to their unique atomic structure, and the use of metallic glasses as electrodes has produced unexpected electrocatalytic degradation effects for many pollutants through combining with electrochemical technology. However, it still is a formidable challenge to find a metallic glass electrode material with both efficient and clean for the catalytic degradation of pollutants. In this work, the Cu55Zr45 metallic glassy ribbons are used as an electrode to degrade azo dyes and show the excellent degradation effect, which can reach 95.6% within 40 min. In the degradation process, almost no additives are produced and Cu55Zr45 metallic glassy ribbons have excellent effects under different pH conditions. Meanwhile, it exhibits good stability for degradation efficiency during the 8 cycle degradation tests of the amorphous alloy electrode. When the copper nanoparticles are exposed on the surface of the ribbons, the oxidized copper obtained synergistically produce activated radicals is the primary degradation mechanism, where the auxiliary degradation mechanisms include electron transfer and the promotion of active chlorine. This research develops a new type of electrode material for wastewater treatment, and the economy and high efficiency of Cu55Zr45 metallic glass endow it the expandable functional applications.

A comprehensive exploration of tartrazine detection in food products: Leveraging fluorescence nanomaterials and electrochemical sensors: Recent progress and future trends.

Azo dyes are widely used as food coloring agents because of their affordability and stability. Examples include brilliant blue, carmoisine, sunset yellow, allura red, and tartrazine (Tar), etc. Notably, Tar is often utilized in hazardous food goods. They are frequently flavoured and combined with food items, raising the likelihood and danger of exposure. Therefore, detecting Tar in food is crucial to prevent health risks. Fluorescence nanomaterials and electrochemical sensors, known for their high sensitivity, affordability, simplicity, and speed, have been widely adopted by researchers for Tar detection. This comprehensive paper delves into the detection of Tar in food products. It extensively covers the utilization of advanced carbon-based nanomaterials, including CDs, doped CDs, and functionalized CDs, for sensitive Tar detection. Additionally, the paper explores the application of electrochemical sensors. The paper concludes by addressing current challenges and prospects, emphasizing efforts to enhance sensitivity, and selectivity for improved food safety.

Synthesis of polymer dots as fluorescent nanoprobe for the detection of Ponceau 4R, an additive color abuse in food.

Abusing organic dyes in industrial food products is an important issue in many countries. Rapid chemical sensing of these compounds can be of great importance during the industrial life of humans. In this work, we synthesized a new fluorescent polymer dot and successfully applied it as an optical probe for the detection of red color abuse in foodstuffs. Ponceau 4R is a red organic dye additive that is used in some foodstuffs such as tomato sauces or pastes. It is too hazardous to human health. Detection of such abusage is challenging. The development of π-conjugated polymer dots having a bright emission band at visible can be a promising probe for the detection of food color additives. A variety of methods and monomers were previously used for their synthesis. Here, the Suzuki Coupling method was employed. The limit of detection (LOD) of the method was obtained 16 nmol L-1 for the detection of Ponceau 4R.

Synthetic azo-dye, Tartrazine induces neurodevelopmental toxicity via mitochondria-mediated apoptosis in zebrafish embryos.

Tartrazine (TZ), or E 102 or C Yellow, is a commonly used azo dye in the food and dyeing industries. Its excessive usage beyond permissible levels threatens human health and the aquatic environment. While previous studies have reported adverse effects such as mutagenicity, carcinogenicity, and reproductive toxicity. Our study aimed to comprehensively evaluate the developmental neurotoxicity of TZ exposure via biochemical and behavioral examinations and explored the underlying mechanism via gene expression analyses. TZ at an environmentally relevant concentration (50 mg/L) significantly induces oxidative stress, altered antioxidant (SOD, CAT and GSH) response, triggered cellular damage (MDA and LDH), and induced neuro-biochemical changes (AChE and NO). Gene expression analyses revealed broad disruptions in genes associated with antioxidant defense (sod1, cat, and gstp1), mitochondrial dysfunction (mfn2, opa1, and fis1),evoked inflammatory response (nfkb, tnfa, and il1b), apoptosis activation (bcl2, bax, and p53), and neural development (bdnf, mbp, and syn2a). Behavioral analysis indicated altered thigmotaxis, touch response, and locomotion depending on the concentration of TZ exposure. Remarkably, the observed effective concentrations were consistent with the permitted levels in food products, highlighting the neurodevelopmental effects of TZ at environmentally relevant concentrations. These findings provide valuable insights into the underlying molecular mechanisms, particularly the role of mitochondria-mediated apoptosis, contributing to TZ-induced neurodevelopmental disorders in vivo.

Changing Despicable Me: Potential replacement of azo dye yellow tartrazine for pequi carotenoids employing ionic liquids as high-performance extractors.

Color is a crucial sensory attribute that guides consumer expectations. A high-performance pequi carotenoid extraction process was developed using ionic liquid-based ethanolic solutions and a factorial design strategy to search for a potential substitute for the artificial azo dye yellow tartrazine. All-trans-antheraxanthin was identified with HPLC-PAD-MSn for the first time in pequi samples. [BMIM][BF4] was the most efficient ionic liquid, and the maximization process condition was the solid-liquid ratio R(S/L) of 1:3, the co-solvent ratio R(IL/E) of 1:1 ([BMIM][BF4]: ethanol), and three cycles of extraction with 300 s each and yielded 107.90 µg carotenoids/g of dry matter. The ionic liquid-ethanolic solution recyclability was accomplished by freezing and precipitating with an average recovery of 79 %. In CIELAB parameters, pequi carotenoid extracted with [BMIM][BF4] was brighter and yellower than the artificial azo dye yellow tartrazine. A color change of 11.08 and a hue* difference of 1.26° were obtained. Furthermore, carotenoids extracted with [BMIM][BF4] showed antioxidant activity of 35.84 µmol of α-tocopherol. These findings suggest the potential of employing the pequi carotenoids to replace the artificial azo dye yellow tartrazine in foods for improved functional properties.

Potential Environmental Contaminants: Exploring Hydrolyzed Dyes in Household Washing Sources and Electrochemical Degradation.

Reactive dyes are often released into the environment during the washing process due to their susceptibility to hydrolysis. The hydrolysis experiment of a pure reactive dye, red 195 (RR 195), and the washing experiment of RR 195-colored fabrics (CFSCs) were carried out successively to explore the sources of hydrolyzed dyes in the washing microenvironment. Reversed-phase high-performance liquid chromatography (RP-HPLC) was used for the analysis of hydrolysis intermediates and final products of reactive red 195. The experimental results indicated that the structure of the dye washing shed is consistent with the final hydrolysate of reactive red 195, which is the main colored contaminant in washing wastewater. To eliminate the hydrolyzed dyes from the source, an electrochemical degradation device was designed. The degradation parameters, including voltage, electrolyte concentration, and dye shedding concentration are discussed in the electrochemical degradation experiment. The electrochemical degradation device was also successfully implemented and verified in a home washing machine.

Electrochemical oxidation of azo dyes degradation by RuO2-IrO2-TiO2 electrode with biodegradation Aeromonas hydrophila AR1 and its degradation pathway: An integrated approach.

Azo dyes are the most varied class of synthetic chemicals with non-degradable characteristics. They are complex compounds made up of many different parts. It was primarily utilized for various application procedures in the dyeing industry. Therefore, it's crucial to develop an economical and environmentally friendly approach to treating azo dyes. Our present investigation is an integrated approach to the electrooxidation (EO) process of azo dyes using RuO2-IrO2-TiO2 (anode) and titanium mesh (cathode) electrodes, followed by the biodegradation process (BD) of the treated EO dyes. Chemical oxygen demand (COD) removal efficiency as follows MB (55%) ≥ MR (45%) ≥ TB (38%) ≥ CR (37%) correspondingly. The fragment generated during the degradation process which was identified with high-resolution mass spectrometry (HRMS) and its degradation mechanism pathway was proposed as demethylation reaction and N-N and C-N/C-S cleavage reaction occurs during EO. In biodegradation studies by Aeromonas hydrophila AR1, the EO treated dyes were completely mineralized aerobically which was evident by the COD removal efficiency as MB (98%) ≥ MR (92.9%) ≥ TB (88%) ≥ CR (87%) respectively. The EO process of dyes produced intermediate components with lower molecular weights, which was effectively utilized by the Aeromonas hydrophila AR1 and resulted in higher degradation efficiency 98%. We reported the significance of the enhanced approach of electrochemical oxidation with biodegradation studies in the effective removal of the pollutants in dye industrial effluent contaminated water environment.

Self-Assembly Nanostructure Induced by Regulation of G-Quadruplex DNA Topology via a Reduction-Sensitive Azobenzene Ligand on Cells.

The control of DNA assembly systems on cells has increasingly shown great importance for precisely targeted therapies. Here, we report a controllable DNA self-assembly system based on the regulation of G-quadruplex DNA topology by a reduction-sensitive azobenzene ligand. Specifically, three azobenzene multiamines are developed, and AzoDiTren is identified as the best G4 binder, which displays high affinity and specificity for G4 DNA. Moreover, the reduction-sensitive nature of the azobenzene scaffold allows AzoDiTren to induce a complete change of the G4 topology in a tissue-specific manner, even at high metal cation concentrations. On this basis, the AzoDiTren-induced G4 conformational switch achieves control of the self-assembly of G4-functionalized DNAs on cells. This strategy enables the regulation of G4 and DNA self-assembly by the bioreductant-responsive ligand.

Historical Perspectives of the Role of NO/NO Donors in Anti-Tumor Activities: Acknowledging Dr. Keefer's Pioneering Research.

The role of nitric oxide (NO) in cancer has been a continuous challenge and particularly the contradictory findings in the literature reporting NO with either anti-cancer properties or pro-cancer properties. This dilemma was largely resolved by the level of NO/inducible nitric oxide synthase in the tumor environment as well as other cancer-associated gene activations in different cancers. The initial findings on the role of NO as an anti-cancer agent was initiated in the late 1990's in Dr. Larry Keefer's laboratory, who had been studying and synthesizing many compounds with releasing NO under different conditions. Using an experimental model with selected NO compounds they demonstrated for the first time that NO can inhibit tumor cell proliferation and sensitizes drug-resistant cancer cells to chemotherapy-induced cytotoxicity. This initial finding was the backbone and the foundation of subsequent reports by the Keefer's laboratory and followed by many others to date on NO-mediated anti-cancer activities and the clinical translation of NO donors in cancer therapy. Our laboratory initiated studies on NO-mediated anti-cancer therapy and chemo-immuno-sensitization following Keefer's findings and used one of his synthesized NO donors, namely, (Z)-1-[N-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1-ium-1,2-diolate (DETANONOate), throughout most of our studies. Many of Keefer's collaborators and other investigators have reported on the selected compound, O2-(2,4-dinitrophenyl) 1-[(4-ethoxycarbonyl)piperazin-1-yl] diazen-1-ium-1,2-diolate (JS-K), and its therapeutic role in many tumor model systems. Several lines of evidence that investigated the treatment with NO donors in various cancer models revealed that a large number of gene products are modulated by NO, thus emphasizing the pleiotropic effects of NO on cancers and the identification of many targets of therapeutic significance. The present review reports historically of several examples reported in the literature that emanated on NO-mediated anti-cancer activities by the Keefer's laboratory and his collaborators and other investigators including my laboratory at the University of California at Los Angeles.

Fifty Years of Diazeniumdiolate Research: A Tribute to Dr. Larry K. Keefer.

The pioneering studies of Dr. Larry Keefer and colleagues with diazeniumdiolates or NONOates as a platform have unraveled the chemical biology of many nitric oxides and have led to the design of a variety of promising therapeutic agents in oncology, gastroenterology, antimicrobials, wound healing, and the like. This dedication to Dr. Larry Keefer briefly highlights some of his studies using the diazeniumdiolate platform in the cancer arena.

Harnessing Efficient ROS Generation in Carbon Dots Derived from Methyl Red for Antimicrobial Photodynamic Therapy.

The emergence of drug-resistant pathogenic microorganisms has become a public health concern, with demand for strategies to suppress their proliferation in healthcare facilities. The present study investigates the physicochemical and antimicrobial properties of carbon dots (CD-MR) derived from the methyl red azo dye. The morphological and structural analyses reveal that such carbon dots present a significant fraction of graphitic nitrogen in their structures, providing a wide emission range. Based on their low cytotoxicity against mammalian cells and tunable photoluminescence, these carbon dots are applied to bioimaging in vitro living cells. The possibility of using CD-MR to generate reactive oxygen species (ROS) is also analyzed, and a high singlet oxygen quantum efficiency is verified. Moreover, the antimicrobial activity of CD-MR is analyzed against pathogenic microorganisms Staphylococcus aureus, Candida albicans, and Cryptococcus neoformans. Kirby-Bauer susceptibility tests show that carbon dots synthesized from methyl red possess antimicrobial activity upon photoexcitation at 532 nm. The growth inhibition of C. neoformans from CD-MR photosensitization is investigated. Our results show that N-doped carbon dots synthesized from methyl red efficiently generate ROS and possess a strong antimicrobial activity against healthcare-relevant pathogens.

Catalytic degradation of crystal violet and methyl orange in heterogeneous Fenton-like processes.

Metals-loaded (Fe3+, Cu2+ and Zn2+) activated carbons (M@AC) with different loading ratios (0.1%, 0.5%, 1%, 5% and 10%) were prepared and employed for catalytic degradation of dye model compounds (crystal violet (CV) and methyl orange (MO)) in wastewater by heterogeneous Fenton-like technique. Compared with Cu@AC and Zn@AC, 0.5% Fe3+ loaded AC (0.5Fe@AC) had better catalytic activity for dyes degradation. The effects of dyes initial concentration, catalyst dosage, pH and hydrogen peroxide (H2O2) volume on the catalytic degradation process were investigated. Cyclic performance, stability of 0.5Fe@AC and iron leaching were explored. Degradation kinetics were well fitted to the pseudo-second-order model (Langmuir-Hinshelwood). Almost complete decolorization (99.7%) of 400 mg L-1 CV was achieved after 30 min reaction under the conditions of CV volume (30 mL), catalyst dosage (0.05 g), H2O2 volume (1 mL) and pH (7.7). Decolorization of MO reached 98.2% under the same conditions. The abilities of pyrolysis char (PC) of dyeing sludge (DS) and metal loaded carbon to remove dye pollutants were compared. The intermediate products were analyzed and the possible degradation pathway was proposed. This study provided an insight into catalytic degradation of triphenylmethane- and aromatic azo-based substances, and utilization of sludge char.

UiO-66 octahedrons for adsorptive removal of direct blue-6: process optimization, interaction mechanism, and phytotoxicity assessment.

The materials for water treatment have been evolving in multitude of dimensions, indicating the importance of water reuse and increasing level of water pollution around the globe. Among the various materials that are utilized in wastewater treatment, the material that has attracted the research community for the past decades is the metal organic framework (MOF). In this work one of the water stable and microporous MOF, UiO-66, and its aminated version has been employed to adsorb an anionic azo dye, direct blue-6 (DB-6), from the aqueous matrix. Performance of both the MOFs was compared to know the efficiency under varying solution conditions. The optimized parameters for DB-6 adsorption by UiO-66 was performed using response surface methodology. This numerical optimization was further extended with canonical and ridge analysis. Under optimal conditions, the materials were exhibiting a good adsorption capacity of 754.4 mg/g. The materials were analyzed in terms of morphology, crystallinity, thermal stability, and surface area using instruments like X-ray diffraction, electron microscopy, thermogravimetric analysis, and BET surface area analysis. The mechanism of interaction between UiO-66 and DB-6 molecule was elucidated with the help of XPS analysis which helps to know the main interacting group of UiO-66. This study was concluded with a phytotoxicity analysis of DB-6 and the antioxidant system of Vigna radiata assessed using pre and post adsorbed water.

Ecofriendly alkali metal cations diffusion improves fabrication of mixed-phase titania polymorphs on fixed substrate by chemical vapor deposition (CVD) for photocatalytic degradation of azo dye.

Controlling the nanoscale synthesis of semiconductor TiO2 on a fixed substrate has fascinated the curiosity of academics for decades. Synthesis development is required to give an easy-to-control technique and parameters for TiO2 manufacture, leading to advancements in prospective applications such as photocatalysts. This study, mixed-phase TiO2(B)/other titania thin films were synthesized on a fused quartz substrate utilizing a modified Chemical vapor depodition involving alkali-metal ions (Li+, Na+, and K+) solution pre-treatment. It was discovered that different cations promote dramatically varied phases and compositions of thin films. The films had a columnar structure with agglomerated irregular-shaped particles with a mean thickness of 800-2000 nm. Na+ ions can promote TiO2(B) more effectively than K+ ions, however Li+ ions cannot synthesize TiO2(B). The amounts of TiO2(B) in thin films increase with increasing alkali metal (K+ and Na+) concentration. According to experimental and DFT calculations, the hypothesized TiO2(B) production mechanism happened via the meta-stable intermediate alkaline titanate transformation caused by alkali-metal ion diffusion. The mixed phase of TiO2(B) and anatase TiO2 on the fixed substrate (1 × 1 cm2) obtained from Na+ pre-treated procedures showed significant photocatalytic activity for the degradation of methylene blue. K2Ti6O12, Li2TiO3, Rutile TiO2, and Brookite TiO2 phase formations produced by K+ and Li + pretreatment are low activity photocatalysts. Photocatalytic activities were more prevalent in NaOH pre-treated samples (59.1% dye degradation) than in LiOH and KOH pre-treated samples (49.6% and 34.2%, respectively). This revealed that our developed CVD might generate good photocatalytic thin films of mixed-phase TiO2(B)/anatase TiO2 on any substrate, accelerating progress in future applications.

Aggregation studies of alpha-lactalbumin induced by edible azo dyes with different sulfonyl group numbers: A comparative study.

As an opaque and complex colloidal mixture, milk is usually present as a positively charged colloid under acidic conditions. Adding negatively charged colloids can lead to protein aggregation in milk. Alpha-lactalbumin (α-La) is an essential component of whey protein and has good physicochemical properties for functional food development. We combined spectroscopy, computer simulations, and other techniques to comparative analyze the mechanisms and characteristics of isolated α-La aggregation induced by CI Acid Red 27 (C27)/CI Acid Red 14 (FB) containing different sulfonyl groups in vitro. The results showed that C27/FB (5.25 × 10-5 mol·L-1 to 3.15 × 10-4 mol·L-1) induced the formation of fibril-like aggregates under acidic conditions (pH 2.0 and 4.0) mainly benefit from hydrophobic and electrostatic forces. Weakening and redshift of α-La's characteristics negative peak were observed (208 nm to 218 nm) on circular dichroism. ß-Crosslinks self-assembly and reorganization of disulfide bonds occurred during protein fibrillation. Moreover, the different redshift intensity of Congo red binding to amyloid fibrils was observed to be induced by C27 (>551 nm) and FB (>536 nm), and the direct observation by TEM demonstrated the ability to induce protein fibrillation is C27 > FB. Edible azo dyes with more sulfonyl groups would possess a stronger ability to induce protein fibrillation.

Porous metal-organic framework-acrylamide-chitosan composite aerogels: Preparation, characterization and adsorption mechanism of azo anionic dyes adsorbed from water.

Micro- and nano-metal-organic frameworks with different adsorption properties were prepared by a time-modulation hydrothermal method. By comparing the adsorption properties, the most effective MIL-68(Fe)-12 was selected to be mixed with chitosan (CS), and porous metal-organic framework-acrylamide-chitosan composite aerogel (PMACA) was prepared by introducing acrylamide prior to glutaraldehyde crosslinking. The adsorption capacity of PMACA doped with acrylamide was as high as 2086.44 mg·g-1. The adsorption performance of PMACA was 1.48 times higher compared to the porous metal-organic framework-chitosan composite aerogel (PMCA) undoped with acrylamide. With the introduction of acrylamide, the stability of PMACA was improved, making it less prone to dispersion and decomposition. Structural characterization and adsorption properties were analyzed using methods such as XRD, FTIR, TGA, SEM, BET, and Zeta potential. The adsorption performance of PMACA was investigated further through batch tests with variables such as adsorbent dosage, pH, contact time, initial CR solution concentration, and temperature. The model fitting of PMACA was consistent with the pseudo-second-order model and the Sips model. The adsorption thermodynamics showed that high temperature promoted spontaneous adsorption behavior. PMACA showed a recovery rate of approximately 86 % after six cyclic adsorption tests. PMACA maintained a recovery rate of roughly 86 % after six cyclic adsorption tests. The combined effects of electrostatic attraction, hydrogen bonding, and π-π conjugation resulted in excellent adsorption performance, while pore filling also contributed to the efficient adsorption of Congo red (CR).

Simultaneous microbial electrochemical degradation of methyl orange and bioelectricity generation using coculture as anode inoculum in a microbial fuel cell.

Methyl Orange, an azo dye, is a widely used colouring agent in the textile industry. The study aimed to investigate the efficiency of bioremediating bacteria in degrading methyl orange. Escherichia coli (E. coli), a Methyl Orange-degrading bacterium, was isolated from cow dung and its biochemical properties were analysed using 16S rRNA sequencing, and MALDI-TOF MS. A pre-cultured strain of Pseudomonas aeruginosa was co-cultured with E. coli in 1:1 ration in a microbial fuel cell (MFC) for simultaneous electricity production and methyl orange degradation. The degradation was combined with biological wastewater treatment at varying Methyl Orange concentrations, and the electrochemical characteristics were analysed through polarisation study, cyclic voltammetry, and electrochemical impedance spectroscopy. The impact of parameters such as anolyte pH, dye concentration, incubation time, and substrate concentrations were also studied. This study confirmed E. coli as an effective methyl orange degrading bacteria with a maximum % degradation efficiency of 98% after 48 h incubation at pH 7.0. The co-culture of isolated microorganisms at 250 mg/L of methyl orange concentration showed a maximum power density 6.5 W/m3. Further, anode modification with Fe2O3 nanoparticles on the anode surface enhanced power production to 11.2 W/m3, an increase of 4.7 W/m3.

Synthesis of an Ortho-Functionalized Tetrafluorinated Azobenzene Phosphoramidite for Incorporation into a Tetrafluorinated Azobenzene-Containing siRNA for Photocontrolled Gene Silencing.

This article presents the detailed synthesis and characterization protocols for an ortho-functionalized tetrafluorinated azobenzene containing siRNA, which has photoswitchable properties. To design this tetrafluorinated azobenzene scaffold, several synthetic steps are performed to generate a symmetrical tetrafluorinated azobenzene diol. This diol is treated with dimethoxytrityl chloride (DMT-Cl) to protect one of the alcohols. Next, the DMT-protected tetrafluorinated monoalcohol is phosphitylated to afford the DMT-phosphoramidite building block used for solid-phase synthesis. This paper also contains the detailed biophysical characterization, biological testing, and photo-switching protocols of an ortho-functionalized fluorinated azobenzene containing siRNA (F-siRNA), which has photoswitchable properties that can be controlled with visible light. First, the F-siRNA was characterized by annealing the sense and antisense strands together and then measuring the circular dichroism (CD) profile and melting temperature (Tm ) of the duplexes. Second, biological testing of the F-siRNA is performed in cell culture to determine their gene silencing efficacy. Finally, their gene-silencing activities are measured after exposure to green light to inactivate the F-siRNA, followed by blue light, which reactivates the F-siRNA. The F-siRNA can be kept inactive for up to 72 hr and reactivated at any time within this 72-hr window. © 2023 Wiley Periodicals LLC.

Applicability of a graphene oxide nanocomposite for fabrication of an electrochemical sensor for simultaneous detection of sunset yellow and rhodamine B in food samples.

Developing a sensitive portable sensor for the determination of food additives is very important. Herein, a simple and sensitive electrochemical sensor has been constructed based on a carbon paste electrode (CPE) modified with graphene oxide (GO) nanosheets for the simultaneous determination of sunset yellow (SY) and rhodamine B (RhB) in phosphate buffer solution (pH = 4). The cyclic and differential pulse voltammetry (CV and DPV) results revealed two well-resolved anodic peaks for SY and RhB with a remarkable increase in oxidation signals of these colorants. Based on this, an electrochemical method was developed for the first time for the simultaneous detection of SY and RhB. Applicability of the sensor was confirmed in various concentrations of two analytes in two linear ranges of 1-20 µM for SY and 1-30 µM for RhB with a limit of detection (LOD) of 10.0 nM and 20.0 nM, respectively. Furthermore, the proposed sensor was successfully employed for the simultaneous detection of SY and RhB in food samples with recoveries of 93.1-106.0% indicating promising potential in practical application.