Neutral Red Research Articles

Multicolor fluorescence regulation of N doped silicon quantum dots and the multiple applications

Currently-reported silicon quantum dots (SiQDs) usually have blue fluorescence, which limits its applications in biological fields, so it is of great significance to develop SiQDs with non-blue fluorescence, especially adjustable multicolor fluorescence. In this study, neutral red was selected as the dopant to prepare a series of N doped silicon quantum dots (N-SiQDs) with adjustable fluorescence colors from blue to orange by simply controlling preparation conditions. Due to the complexion between the N-SiQDs and Cu2+, the fluorescence of N-SiQDs was quenched, and thus N-SiQDs were employed as the fluorescent probe for the detection of Cu2+ in tap water and artificial cerebrospinal fluid with good selectivity, wide linear range (0.05–5 μM) and low detection limit (0.02 μM). In addition, the N-SiQDs were applicable to cell imaging and intracellular detection of Cu2+ as the orange fluorescence of the N-SiQDs could avoid background fluorescence interference from biological samples. Furthermore, N-SiQDs of varied fluorescence colors could be well solidified, exhibiting the potential for the optical device. The present study provided an easy-to-handle and effective way to synthesize multicolor fluorescent SiQDs.

Synthesis of a Mixed-Ligand H-Bonded Cu Coordination Polymer: Exploring the pH-Dependent High Photocatalytic Degradation of Rhodamine 6G, Methyl Violet, Crystal Violet, and Rose Bengal Dyes under Room Illumination.

A new mixed-ligand H-bonded coordination polymer {[Cu2(Or)2(Bimb)3]·4H2O} n (KA@CP-S) has been prepared hydrothermally using basic copper carbonate with 1,4-bis[(1H-imidazol-1-yl)methyl]benzene (Bimb) and potassium orotate (OrK) ligands. According to topological studies, KA@CP-S has a new topology with a three-connected uninodal net with point symbol (PS) {82·12}2{8}3. The KA@CP-S was employed as a catalyst for screening of a series of harmful cationic, anionic, and neutral organic dyes in contaminated water. The photocatalytic degradation study shows that it exhibits good catalytic efficiency for cationic dyes like Crystal Violet (CV, 75.8%), Methyl Violet (MV, 76.8%), and Rhodamine 6G (Rh6G, 86.5%) and Rose Bengal (RB, 76.1%), which is an anionic dye, while for a neutral dye, its catalytic efficiency is only 72% (Neutral Red) at ambient temperature. The effect of pH on photocatalytic degradation was also analyzed. The degradation experiment reveals that the detection limits of KA@CP-S for mostly catalyzed colorant concentrations in contaminated water are 0.60 ppm (CV), 0.20 ppm (RB), 0.33 ppm (MV), and 0.20 ppm (Rh6G) at pH 12, 4, and 10. The degradation of dyes follows pseudo-first-order kinetics. The excellent catalytic property and regeneration ability of KA@CP-S make it a potential and efficient future remedial material for the detection and separation of toxic dyes from wastewater contaminated by industrial effluents.

Fabrication of poly(itaconic acid)-g-potassium alginate aerogels as eco-friendly biosorbents for removal of cationic dyes

Biosorbents derived from itaconic acid (IA) with abundant carboxyl groups are viewed as ideal materials for the removal of cationic dyes. However, it is still challenging to prepare IA-based biosorbents with satisfactory structural stability and adsorption ability. In this work, a novel poly(itaconic acid)-g-potassium alginate (PIA-g-PA) aerogel was prepared as a biosorbent and was then utilized to remove cationic dyes. The results presented that the as-prepared PIA-g-PA aerogel possessed outstanding adsorption capacities for cationic dyes based on the adsorption mechanism of electrostatic interaction. The adsorption process was well described by the pseudo-second-order model and the Freundlich model. The maximum adsorption capacities of the as-prepared aerogel toward methylene blue (MEB), malachite green (MG) and neutral red (NR) were 1892.07 mg·g−1, 786.96 mg·g−1 and 1169.23 mg·g−1, respectively. The adsorption capacity of aerogel toward cationic dyes significantly decreased with an increment of ionic strength. Meanwhile, the thermodynamic study indicated that the adsorption of cationic dyes onto the PIA-g-PA aerogel was spontaneous as an endothermic process. Additionally, the removal efficiency of as-prepared PIA-g-PA aerogel was still above 90.00% even after 10 cycles. Hence, the PIA-g-PA aerogel can be regarded as an eco-friendly adsorbent for the potential remediation of dye pollution in industrial effluents.

Bifunctional Self-Penetrating Co(II)-Based 3D MOF for High-Performance Environmental and Energy Storage Applications

A new metal–organic framework, [Co3(BTC)2(Bimb)3(H2O)2]n (KA@MOF-S), has been synthesized under hydrothermal conditions [H3BTC = 1,3,5-benzenetricarboxylic acid, Bimb = 1,4-bis[(1H-imidazol-1-yl)methyl]benzene] and characterized by single-crystal X-ray diffraction (SC-XRD), elemental analysis, powder X-ray diffraction (PXRD), and Fourier-transform infrared spectroscopy (FT-IR). KA@MOF-S is a self-penetrating three-dimensional (3D) framework, which shows a 3,4,4,T25 underlying topological net. The structural diversity of KA@MOF-S indicates that the bis-imidazole and polycarboxylate play important roles in tuning the dimensionality and structure of the KA@MOF-S. The solid-state luminescence, thermal stability property, recyclability, adsorption studies, and photocatalytic effectiveness for KA@MOF-S toward the degradation of organic dyes such as Rhodamine 6G (Rh6G), Crystal Violet (CV), Methyl Violet (MV), Safranin O (SO) and Neutral Red (NR) in contaminated water have also been explored in detail. Promising degradation efficiencies of about 98.32% (Rh6G), 96.54% (CV), 92.30% (MV), 92.24% (SO), and 90.30% (NR) under sunlight irradiation in 150 min are observed. KA@MOF-S shows good electrochemical characteristics, which are proven by cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) analysis under an aqueous 1 M H2SO4 electrolyte. The electrochemical measurements of the as-prepared electrode material deliver a high specific capacity of 648 F g–1 at a current density of 1 A g–1. The KA@MOF-S electrode material achieves a better capacitance retention of 89.25% after 1000 cycles at 10 A g–1. KA@MOF-S is revealed as a promising novel electrode material for high-performance energy storage applications.

Neutral red dye adsorption on carbon nano-onions: viability assay interference and adduct characterisation

Carbon nano-onions (CNO) are versatile carbon nanomaterials with many potential biomedical applications. In this work, the interaction of submerged arc discharge in water (SADW) produced CNOs with the neutral red (NR) dye was studied. This dye is used in the in vitro toxicity NR assay, one of the most commonly used dye-based procedures to determine cell viability. Firstly the NR assay was carried out in murine fibroblast cell cultures exposed to CNOs. It was demonstrated that this assay produced invalid results due to the strong adsorption of NR on the CNOs. Fourier transform infrared spectroscopy (FTIR) and x-ray photoelectron spectroscopy (XPS) studies confirmed the effective adsorption of the NR on CNOs and π-π stacking as the main interaction between them. The adsorption of NR on the CNOs was evaluated by studying the decrease of the dye solution absorbance. The influence of different experimental conditions such as pH and CNOs dosage was evaluated: absorbance was found to diminish with the CNO dosage. For the maximum dosage used of 240 μg ml−1, the highest absorbance drops of −85% at pH 7 and −78% at pH 4 were registered. The adsorption process was found to be described best by a pseudo-first order (PFO) kinetics model (R 2 = 0.99), with a kinetic adsorption constant of k 1 = 0.02 min−1 and achieving an estimated sorption capacity of 3866 mg of dye per gram of CNOs. This is one of the highest values ever reported for dyes’ adsorption on carbon materials. Lastly, density functional theory (DFT) calculations were carried out to gain further insights into the interaction. These studies suggest a CNO highest occupied molecular orbital (HOMO)/NR lowest unoccupied molecular orbital (LUMO) electron density transfer as the main orbital interaction.

Insights of ethyl acetate fraction from Vassobia breviflora in multidrug-resistant bacteria and cancer cells: from biological to therapeutic

ABSTRACT Cancer and infectious diseases are among the leading causes of death in the world. Despite the diverse array of treatments available, challenges posed by resistance, side effects, high costs, and inaccessibility persist. In the Solanaceae plant family, few studies with Vassobia breviflora species relating to biological activity are known, but promising results have emerged. The phytochemicals present in the ethyl acetate fraction were obtained using ESI-MS-QTOF, and the antioxidants assays 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2’-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) radical capture (ABTS), plasma ferric reduction capacity (FRAP), and total antioxidant capacity (TAC). Cytotoxic activity was evaluated by MTT, Neutral Red, and lactate dehydrogenase (LDH) released. The production of reactive oxygen species, nitric oxide, and purinergic enzymes was also investigated. Antibacterial activity was measured through minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and antibiofilm activity, in addition to genotoxicity in plasmid DNA. Five major masses were identified D-glucopyranose II, allyl disulfide, γ-lactones, pharbilignoside, and one mass was not identified. V. breviflora exhibited relevant antioxidant and cytotoxic activity against the HeLa cell line and enhanced expression effect in modulation of purinergic signaling. Antibacterial activities in the assays in 7 ATCC strains and 8 multidrug-resistant clinical isolates were found. V. breviflora blocked biofilm formation in producing bacteria at the highest concentrations tested. However, there was no plasmid DNA cleavage at the concentrations tested. Data demonstrated that V. breviflora exhibited an antioxidant effect through several methods and proved to be a promising therapeutic alternative for use against tumor cells via purinergic signaling and multidrug-resistant microorganisms, presenting an anti-biofilm effect.

Hydrogen Evolution Reaction By Metal-Free Poly-Neutral Red Electrocatalyst

While electric power supply by renewable sources such as solar and wind has become viable for their significant cost reduction, its intermittency demands urgent development of large scale storage technologies. Although conversion of electrical energy into storable hydrogen via electrolysis of water is ideal, noble metals and their oxides are used as electrocatalysts for their activities and stabilities. Alternative electrocatalysts out of abundant elements are needed for sustainable technological development.Recently, some metal-free organic conductive polymers with hydrogen-bonding capabilities were found to exhibit high electrocatalytic activities towards hydrogen evolution reaction (HER) [1,2]. We have succeeded electropolymerization of neutral red (NR) resulting in a formation of conductive poly-NR (PNR) that shows a relatively high HER catalytic activity [3]. PNR possesses hydrogen-bonding N atoms as annelated in the phenazine aromatic system as well as those in the amino substituents. Electrochemical analysis combined with in situ spectroscopy as well as DFT calculation was performed to clarify the mechanism and kinetics of HER electrocatalysis by PNR.This films of PNR were obtained by electropolymerization on F-doped SnO2 coated conductive glass (FTO, Asahi Glass) and SIGRATHERM® GFA5 Carbon felt with potential cycling between -0.2 and 1.2 V (vs. Ag/AgCl) at 50 mV s-1 for 50 times in a 5 mM NR - 0.1 M H2SO4 aqueous solution under N2. Polyaniline (PANI) was also obtained by the same method for comparison. The HER catalysis was evaluated by linear sweep voltammetry (LSV) in a 1 M trifluoromethanesulfonic acid (TfOH) under N2. The film samples were characterized by Fourier transform infrared spectroscopy (FT-IR), UV-visible spectroscopy. In-situ UV-visible spectroelectrochemical monitoring of the reaction intermediate was carried out to determine the rate of HER.PNR undergoes a pseudo-reversible reduction that shifts -61.8 mV/pH under acidic conditions and HER takes off right at this point (Fig. 1, a). Coupling of the same number of protons / electrons is expected as the electrochemical stoichometry from the observed Nernstian relationship, namely, resulting in a singly reduced PNR-H or doubly reduced PNR-H2 as depicted in Fig. 1 b. Protonation of N atoms was reasonably expected and also supported by the DFT calculation. The hydrogen atoms stabilized in the reaction intermediate can be associated to release H2 (Tafel mechanism) to complete the cycle of electrocatalysis of HER.Reduction of PNR in fact is associated with a color change. The broad reddish absorption of PNR peaking at around 500 nm attenuates to change the color to a pale yellow by constantly applying -0.15 V vs. RHE to produce PNR-H and/or PNR-H2 state as shown in Fig. 1c. Gradual recovery of the original red PNR was observed under open circuit under N2, associated with the H2 release. Thus, the rate of the spectral change is analyzed to determine the rate of the Tafel process. Pseudo-first order reaction rate law can be applied as proton is abundant and its concentration is constant, so that the rate of HER (r H2) is simply described as the rate of consumption of PNR-H and/or PNR-H2 as, r H2=-dC PNR-H2/dt =-kt (1)The ratio of PNR-H and PNR-H2 as compared to their initial amount (x PNR-red) was defined from the absorbance at 545 nm before and after reduction as, x PNR-red = C PNR-red/C 0-PNR-red = exp (-kt) (2)Good fitting of the experimental data was obtained to yield a pseudo-first order reaction rate constant of 9.98×10-4 s-1 for this rate-limiting step.

Electropolymerization of Neutral Red

Hydrogen bonding conductive polymers have attracted attention as metal-free electrocatalysts for energy conversion (1)(2). Neutral red (NR), a pH indicator in the family of phenazine dyes, can be polymerized into poly-NR (PNR) just like aniline (ANI) does into poly-ANI (PANI). Due to the presence of hydrogen bonding N atom, PNR has been found to act as a good catalyst for hydrogen evolution reaaction (HER) (3). Although electropolymerization to achieve these polymer films is believed to take off by oxidation of the monomers into their respective radicals, potential sweep and cycling in a wide potential range are almost always employed, in other words, the films are obtained in the course of cyclic voltammetry (CV) in the monomer solutions. A clear benefit of such a method is to facilitate monitoring of the film growth, as the electrodeposited polymers often show a redox behavior. However, it is not easy to elucidate electrochemical stoichiometry and its Faradic efficiency by charge integration from the CVs during the film growth. If the electrochemical oxidation of the monomers is the only important process, potentiostatic electrolysis and chronoamperometric (CA) monitoring should work as well and be beneficial to the understanding of the reaction mechanism. However, to our knowledge, no such studies have been reported so far.In this study, several different protocols of electrolysis have been tested and compared for electropolymerization of NR, i.e., potential sweep/cycling (CV), potentiostatic electrolysis (CA), potential stepping pulsed electrolysis (PP), with variation of conditions and also by their combinations. While reddish black thin films of PNR were nicely obtained by the standard CV method up to +1.2 V vs. Ag/AgCl to oxidize NR and down to -0.2 V to observe reduction of NR as well as electrodeposited PNR in acidic aqueous solutions of NR + H2SO4, the CA method to apply a constant potential of +1.05 V, sufficiently positive to promote oxidation of NR resulted in in a significant slowdown of PNR growth. The CA method, however, did result in a formation of PNR. Comparison of anodic charge for monomer oxidation both in the CV and CA methods with the optical density (O.D.) of the resulting PNR proved proportionality of O.D. to charge with the same O.D./charge ratios, thus the same Faradic efficiencies. In fact, CA showed a drastic decrease of current down to a rather small steady-state value. This was not caused by depletion of NR at the vicinity of the electrode, but by slowdown of charge transfer kinetics, as the introduction of forced convection by employing a rotating disk electrode (RDE) did not result in any enhancement of current. On the other hand, the anodic peak current only slightly decreased over multiple potential cycling in the CV method. The peak current was approximately linearly proportional to the square root of the scan rate, so that fast charge transfer to hit the diffusion limit of NR was achieved in the CV method.The cause of the difference of charge transfer kinetics was further studied. Anodic growth of PNR naturally results in doping of anions, in this case sulfate, to stabilize polarons to achieve conductivity of PNR. Careful observation of CVs found presence of a couple of small peaks which correspond to doping / dedoping at around +0.5 V. Electrodeposition of PNR by the CV method with variation of negative end potential revealed the importance of dedoping of sulfate to refresh the surface of PNR to be favorable to the oxidation of NR, not the reduction /re-oxidation of the existing PNR. Thus, the PP method to switch the potential between that for the oxidation of NR monomer and the one for dedoping of sulfate from PNR (not the reduction of PNR) achieved the fastest growth of PNR.The above-documented understanding of the electropolymerization of NR will be explained in a quantitative manner along with the experimental data. It is also interesting to mention the difference of the absorption spectra of the PNR films between those obtained by CV and CA methods, indicating their differences in the electronic structure to let us anticipate their differences in the HER electrocatalysis. Reference: Coskun H. al.，Adv. Mater. 32, 25, e1902177 (2020).Coskun H. et. al.， Sustainable Syst. 5, 25, 2000176 (2021).Yuya H al.，The ECS spring meeting abstract 1A17 (2021).

In vitro immunomodulatory and antioxidant effects of oligopeptides and four characteristic peptides in black-bone silky fowl (Gallus gallus domesticus Brisson).

Black-bone silky fowl (Gallus gallus domesticus Brisson) is considered to have strengthening effect on the body and immunomodulatory effects. The black-bone silky fowl peptide (BSFP) was produced by enzymatic digestion of the whole black-bone silky fowl (including the head and claws) after removal of the viscera. Afterwards, the four of the characteristic peptides Glu-Phe (EF), Glu-Glu-Leu (EEL), Glu-His-Pro-Thr (EHPT), Ala-Gly-Gly-His (AGGF) of the BSFP were identified by HPLC-MS/MS. The preventive effects of BSFP and the four characteristic peptides on antioxidant and immunomodulation were investigated. The antioxidant capacity was assessed by in vitro HepG2 intracellular reactive oxygen species (ROS). The immunomodulatory experiments were conducted by measuring the effects of the BSFP and four peptides on the proliferation of splenocytes, T and B lymphocytes cells, the CD4+ /CD8+ T lymphocytes ratio, and the phagocytic capacity of macrophages and the nitric oxide (NO) content of macrophages. The four peptides of BSFP showed strong antioxidant capacity, with the most potent peptide for intracellular ROS being AGGF, with 56% inhibition. AGGF, EF, and BSFP showed highly positive effects on splenocyte proliferation and when Concanavalin A (ConA) was used as a stimulus for T lymphocytes and lipopolysaccharide (LPS) as a stimulus for B lymphocytes, the peptides stimulated cell proliferation in a dose-dependent manner. Of these, EF, AGGF, and BSFP promoted the proliferation of T lymphocytes; EF, EHPT, and BSFP significantly promoted the proliferation of B lymphocytes. EHPT and BSFP increased the CD4+ /CD8+ ratio of T cells. Needle aspiration of neutral red was significantly promoted by macrophages treated with peptides other than EF. In addition, EEL, EHPT, AGGF, and BSFP had a promotive effect on NO production in phagocytes. The results indicate that BSFP is a peptide product with good immunomodulatory functions, four peptides identified from BSFP show outstanding effects in terms of antioxidant properties and immunomodulation. PRACTICAL APPLICATIONS: In this study, the amino acid composition and relative molecular masses of the black-bone silky fowl peptide were analyzed, while the four peptides with significant effects on antioxidant and immunomodulatory properties in black-bone silky fowl peptide were identified by HPLC-MS/MS technique. Positive effects of black-bone silky fowl peptide and its four peptides on antioxidant capacity and immunomodulatory ability as revealed by cell experiments. The results of this experiment provide a preliminary theoretical basis for the development of new functional foods using black-bone silky fowl peptide and their characteristic peptides.

Bivalve Oocyte Inviability Revealed Using a Simple Staining Technique

Photo 1. Cerastoderma edule (Linnaeus, 1758). (A) Emerged animals at low tide, (B) submerged animals with foot (F) and inhalant (IS) and exhalent (ES) siphons deployed. Animals in (A) and (B) are in their 3rd year (two annual growth rings are visible, corresponding to periostracal thickening) and thus both sexually mature. (C) Oocytes (OC) double-stained with Neutral Red vital stain and Trypan Blue mortal stain. Left, normal oocyte, right, dead oocyte. TB, undissolved Trypan Blue stain. (D) Oocytes stained with Neutral Red only; normal oocytes (NO) stain red, while dead oocytes do not stain. The TB stain proved effective, but cumbersome and costly to use in routine studies, while the more convenient and cost-efficient Neutral Red stain alone provided the same information. Photo credit: D. Chérel. These photographs illustrate the article “Evolutionary and ecological insights from vital staining of bivalve oocytes: A Red Queen at the sweepstakes?” by Peter G. Beninger, Daphné Chérel, Gaël Le Pennec, and Sandra E. Shumway published in Ecosphere. https://doi.org/10.1002/ecs2.4047

Corrosion Inhibition Efficiency, Experimental and Quantum Chemical Studies of Neutral Red Dye for Carbon Steel in Perchloric Acidic Media

The Neutral Red (NR) has been investigated as a corrosion inhibitor for carbon steel (C-steel) in 1M perchloric acid using a weight loss method and theoretical calculations based on density functional theory (DFT). The obtained results revealed that NR is an effective inhibitor and its inhibition efficiency increases with the increasing concentration to attain 89.50 % at 5•10-3 M at 293 K. The thermodynamic parameters as enthalpy, entropy and Gibbs free energy for both dissolution and adsorption processes are calculated and discussed. Moreover, the free energy of adsorption showed that the corrosion inhibition takes place by a spontaneous physicochemical adsorption of inhibitor molecules on the C-steel surface. The results show that the calculated values of the quantum chemical parameters indicate a possible existing link between the effectiveness of the inhibitor and its electronic properties.

Ultrasound-Assisted Dispersive Liquid-Liquid Microextraction Using Deep Eutectic Solvents (DESs) for Neutral Red Dye Spectrophotometric Determination.

Deep eutectic solvents (DES), which have low toxicity and are low cost, biodegradable, and easily synthesized, were used for the extraction of neutral red (NR) dye before its spectrophotometric analysis. DES, containing choline chloride as a hydrogen bond acceptor and phenol as a hydrogen bond donor with a molar ratio of 1:2, was used for the extraction of NR dye from aqueous media. The possible interaction of different DESs with NR was studied using density functional theory (DFT) calculations. Experimentally, a UV-visible spectrophotometer was used for the quantitative analysis. The most important parameters affecting method performance, such as pH, extraction temperature, DES type, its volume, THF volume, sonication time, and centrifugation time, were optimized. The developed method provides exceptional sensitivity in terms of LOD and LOQ, which were 2.2 and 7.3 µg/L respectively. The relative standard deviation was 1.35–1.5% (n = 10), and the pre-concentration factor was 40. The method was found to be linear in the range of 2–300 µg/L (R2 = 0.9967). The method was successfully used for the determination of NR in wastewater samples. Finally, the DES-based method presents operational simplicity, high sensitivity, and rapid determination (<5 min) compared with other analytical procedures.

Dyestuff chemistry auxiliary instant immune-network label strategy for immunochromatographic detection of chloramphenicol

Commercial immunochromatographic assay (ICA) is a convenient tool for controlling antibiotic abuse. Although great efforts have been made to improve the detection performance and quantitative capabilities, simplify the manufacturing process of commercial ICA is rarely mentioned. Here, a proof-of-principle work are developed to solve the above problem. Inspired by dyestuff chemistry, we developed an instant immune-network label strategy by dynamic protonation capacity of neutral red (NR), achieving a desirable labeling efficiency (＜1min), and applying for ICA detection of chloramphenicol (CAP). Benefits from the efficiently protonation of NR, lengthy probe production time and organic reagents can be avoided, displaying excellent strip production efficiency and detection performance. Eventually, this strategy presents a visual limit of detection (vLOD) at 3 ng/mL, cut-off value is 9 ng/mL. The assay recoveries in milk and honey were 74.45–107.15 %, with the total RSD of 1.62–6.90 %. We envision that this strategy raises the possibility of commercializing of laboratory prototype products.

Significant Differences in the Reversal of Cellular Stress Induced by Hydrogen Peroxide and Corticosterone by the Application of Mirtazapine or L-Tryptophan

Depression is a prevalent and debilitating disease worldwide. This pathology is very complex and the lack of efficient therapeutic modalities, as well as the high rates of relapse, makes the study and treatment of depression a global healthcare challenge. Thus, an intense investigation of this disease is crucial and urgent. In this study, we focused on hydrogen peroxide and corticosterone-induced stress on SH-SY5Y and HT-22 cells. Additionally, we aimed to study the potential attenuation of these induced stress with the exposure of both cells to mirtazapine and L-tryptophan, focusing on cell viability assays (MTT and Neutral Red) and reactive oxygen species production assays (DCFDA fluorescence). Taken together, our results indicate that mirtazapine and L-tryptophan counteract the cellular stress induced by hydrogen peroxide but not by corticosterone, revealing a potential role of these agents on oxidative stress relief, highlighting the role of serotonergic pathways in the oxidative stress present in depressed individuals. This study allows the investigation of depression using cellular models, enabling the screening of compounds that may have potential to be used in the treatment of depression by acting on cellular mechanisms such as oxidative stress protection.

WITHAFERIN A CITOTOXICITY IN NORMAL KERATINOCYTES: AN IN VITRO STUDY

<h3>Objectives</h3> Epithelial tissue main function is the lining of connective tissue and is characterized by juxtaposition of epithelial cells. Keratinocytes are the main cells of epithelial tissue, and they are responsible for keratin synthesis. HaCat cells are a human keratinocyte lineage widely used for in vitro studies. Withaferin A (WA) is a highly oxygenated steroidal lactone with anti-angiogenic, proapoptotic, and antiproliferative properties, and several studies demonstrated its cytotoxic effect in different types of neoplasms. This study main objective was to explore WA's effect in normal epithelial cells lineage. <h3>Study Design</h3> HaCat cells were subjected to cell viability tests (The MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay, Neutral Red assay, and Picogreen assay) and measurement of intracellular reactive species dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay after 24 hours of treatment in different WA concentrations. <h3>Results</h3> WA was not able to induce oxidative stress in normal keratinocyte cells and only the higher dose tested (7 µM) was a capable of decreased cell viability, but not enough to induce cell death. <h3>Conclusions</h3> Although this drug has known therapeutic potential in the treatment of different types of cancer, we can conclude that WA does not disrupt the function of normal epithelium.

Rhein induces changes in the lysosomal compartment of HeLa cells.

Rhein is an anthraquinone found in Rheum palmatum, used in Chinese medicine. Due to potential anticancer properties, the study assessed its effect on the lysosomal compartment, which indirectly influences cell death. The experiment was performed on HeLa cells by treating them with rhein at concentrations of 100-300 µM. LC3-II protein and caspase 3/7 activity, level of apoptosis, the concentration of reactive oxide species (ROS), and mitochondrial potential (Δψm) were evaluated by the cytometric method. To evaluate the permeability of the lysosomal membrane (LMP), staining with acridine orange and the assessment of activity of cathepsin D and L in the lysosomal and extralysosomal fractions were used. Cell viability was assessed by -(3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) (MTT) and neutral red(NR) assays. Changes in cells were also demonstrated at the level of electron, optical, confocal, and fluorescence microscopy. Inhibition of autophagy was done using chloroquine. Rhein-induced degradation processes were confirmed by an increase in the number of primary lysosomes, autophagosomes, and autolysosomes. At high concentrations, rhein caused the generation of ROS, which induced LMP expressed by quenching of acridine orange fluorescence. These results correlated with a reduction of lysosomes, as visualized in graphical modeling, with the decreased uptake of NR by lysosomes, and increased activity of cathepsin D and L in the extralysosomal fraction. The studies also showed an increase in the activity of caspase 3/7 and a decrease in the expression of Bcl-2 protein, indicative of rhein-stimulated apoptosis. At the same time, we demonstrated that preincubation of cells with chloroquine inhibited rhein-induced autophagy and contributed to increased cytotoxicity to HeLa cells. Rhein also induced DNA damage and led to cycle arrest in the S phase. Our results indicate that rhein, by inducing changes in the lysosomal compartment, indirectly affects apoptosis of HeLa cells and in combination with autophagy inhibitors may be an effective form of anticancer therapy.

A pillar[5]arene-based crosslinked polymer material for selective adsorption of organic dyes

Industrial wastewater containing organic dyes poses severe threats to the global aquatic ecosystem. The exploration of low-cost and environmentally friendly adsorbents has become one major task for the fast and effective elimination of organic dye contaminants. In this study, we fabricate a new type of polymeric dye adsorbent (P1) by crosslinking bihydrazide-functionalized pillar[5]arene with trimesoyl chloride as linkers. Benefiting from the π-electron rich cavity of pillar[5]arene, P1 has demonstrated outstanding potential in the selective adsorption and separation of small cationic dyes. Kinetic experimental results prove that the adsorption behaviors for methylene blue (MB) and neutral red (NR) are accurately matched with the pseudo-second-order model and Freundlich isotherm model. In addition, the integral adsorption rate is determined by both external diffusion and intra-particle diffusion. The pillararene-based polymer adsorbent can be recycled five times with almost no loss of adsorption efficiency, holding great potential to function as an available material for wastewater regeneration and purification.

Metal-organic frameworks-derived CoFeN-NC materials with the enhanced catalytic activity and selectivity for the degradation of organic dyes via adsorption and heterogeneous photo-Fenton

Nanoscale iron-based materials are widely used as photocatalytic materials for catalytic oxidative degradation of organic dyes in water. Here, a series of MOFs derived nitrogen doped cobalt iron bimetallic carbon composite nanomaterials (CoxFe1-xN-NCs) were prepared by self-assembly and annealing treatment, and their application in the removal of organic dyes in water was investigated by the synergistic effect of adsorption and photo-Fenton. The study found that the Co0.8Fe0.2N-NC exhibit superior catalytic performance for different types of organic dyes. For example, when the concentration of MB was 40 mg L-1, the degradation rate constant was 3.88 × 10-2 min−1, which were 2.9 and 25.2 times the corresponding values of the Fenton-like and photocatalytic system, respectively. Meanwhile, compared with azo dyes Methyl Orange and Congo Red (MO and CR), Co0.8Fe0.2N-NC has obvious selective catalysis for non-azo dyes Methylene Blue, Malachite Green, Rhodamine B and Neutral Red (MB, MG, RhB and NR). Moreover, the reaction of cobalt iron active centers with hydrogen peroxide (H2O2) further promotes the generation of active substances (·OH, ·O2– and h+), speeding up the degradation of organic dyes. These results suggest that the synergistic effect of adsorption and photo-Fenton may provide new clues for the treatment of organic pollutants in wastewater.

Electropolymerisation of brilliant cresyl blue and neutral red on carbon-nanotube modified electrodes in binary and ternary deep eutectic solvents

Brilliant cresyl blue (BCB) and neutral red (NR) have been electropolymerized in binary and ternary deep eutectic solvents (DES) on glassy carbon electrodes (GCE) modified with multiwalled carbon nanotubes (CNT). The influence of binary and ternary DES composition on the polymer film properties was evaluated. Cyclic voltammetry and electrochemical impedance spectroscopy were used to characterise the PBCB and PNR films. PBCB/CNT/GCE and PNR/CNT/GCE platforms with polymer formed in ternary DES led to an improvement of the electrochemical properties of the modified electrodes compared to polymer synthesised in the corresponding binary DES. The second hydrogen bond donor tuned the DES characteristics, leading to a sensor platform with higher sensitivity. The PNR/CNT/GCE prepared in different binary and ternary DES were successfully tested for ascorbate sensing and demonstrated the applicability of the sensor architectures.

Facile preparation of floatable carboxymethyl cellulose-based composite hydrogel for efficient removal of organic dyes

Hydrogels have become efficient adsorbents in treatment of organic dyes from wastewater. However, the drawback of difficulty in separation and collection limited their applications. Herein, a series of floatable polyacrylamide/carboxymethyl cellulose‑copper sulfide (PAM/CMC-CuS) hydrogels were designed. The PAM/CMC-CuS hydrogel could not only be easily collected from the wastewater, but also selectively adsorb cationic dyes (Rhodamine B (RhB) and Neutral red (NR)) from the mixed solutions with different oppositely charged dyes. PAM/CMC-CuS hydrogel exhibited faster adsorption rate and higher adsorption capacity than that of PAM/CMC hydrogel. And the adsorption kinetic data were well described by pseudo-second-order model and adsorption isotherm data fitted well with Langmuir equation. Besides, PAM/CMC-CuS hydrogel exhibited excellent reusability and stability that no apparent decrease in removal efficiency was observed after five cycles. Altogether, the good adsorption capacity, floatability, selectivity and reusability will promote the PAM/CMC-CuS hydrogel to be a superior adsorbent in removal cationic dye from wastewater.