Mixture Of Tannic Acid Research Articles

Synergistic strengthening of PVA ionic conductive hydrogels using aramid nanofibers and tannic acid for mechanically robust, antifreezing, water-retaining and antibacterial flexible sensors

Ion-conductive hydrogels with multi-functionality have gained significant attraction as flexible sensors in various fields such as wearable health monitoring and human motion detection, owing to their high ion conductivity, excellent flexibility and stretchability, and easy availability. In this work, multifunctional ion-conductive hydrogel with excellent mechanical properties, antifreezing properties, water retention and antibacterial performance was fabricated by the freeze–thaw crosslinking between polyvinyl alcohol (PVA) and aramid nanofibers (ANF), and the subsequent solution immersion crosslinking in a mixture of tannic acid (TA) and CaCl2 solution (DMSO/H2O as co-solvent). The rational engineering of a multi-spatial distributed hydrogen bond and Ca2+ coordination bond networks within the hydrogel led to a significant improvement in mechanical properties. Furthermore, through the introduction of TA and binary solvents (DMSO/H2O), the hydrogel had witnessed a substantial enhancement in its antimicrobial properties and water retention capacity. The resultant PAT5/CaCl2-5% (DMSO/H2O) hydrogel exhibited outstanding elongation at break (754.73%), tensile strength (6.25 MPa), electrical conductivity (3.09 S/m), which can be employed in flexible sensors to monitor real-time functional motion for human under diverse conditions. As such, this innovation opens up a novel pathway for envisioning flexible sensor devices, particularly in the realm of human activity monitoring.

An Antibacterial and Antiadhesion In Situ Forming Hydrogel with Sol–Spray System for Noncompressible Hemostasis

Noncompressible hemorrhage is a major cause of posttrauma death and occupies the leading position among potentially preventable trauma-associated deaths. Recently, multiple studies have shown that strongly adhesive materials can serve as hemostatic materials for noncompressible hemorrhage. However, the risk of severe tissue adhesion limits the use of adhesive hydrogels as hemostatic materials. Here, we report a promising material system comprising an injectable sol and liquid spray as a potential solution. Injectable sol is mainly composed of gelatin (GEL) and sodium alginate (SA), which possess hemostasis and adhesive properties. The liquid spray component, a mixture of tannic acid (TA) and calcium chloride (CaCl2), rapidly forms an antibacterial, antiadhesive and smooth film structure upon contact with the sol. In vitro and in vivo experiments demonstrated the bioabsorbable, biocompatible, antibacterial, and antiadhesion properties of the in situ forming hydrogel with a sol-spray system. Importantly, the addition of tranexamic acid (TXA) enhanced hemostatic performance in noncompressible areas and in deep wound hemorrhage. Our study offers a new multifunctional hydrogel system to achieve noncompressible hemostasis.

Iron Gall Ink Revisited: A Surfactant-Free Emulsion Technology for Black Hair-Dyeing Formulation

Inspired by the redox reactions in the preparation of the iron gall ink that has been used in Europe since the Middle Ages, we developed a technology for forming the oil-in-water emulsions, without any surfactants and emulsifiers, by homogenizing a mixture of tannic acid, gallic acid, Fe(D-gluconate)2, and natural oil, which are all approved as cosmetic ingredients. Various plant-derived oils, such as argan oil, olive oil, sunflower oil, grape seed oil, hemp seed oil, peppermint oil, rosemary oil, and ylang-ylang oil, were used as an oil phase for the emulsion formation, and all the fabricated emulsions exhibited the capability of black hair-dyeing. This surfactant-free emulsion technology for combining the hair-dyeing capability of Fe3+–tannin complex with the hair-fortifying property of natural oil would have great impact on the hair-cosmetic industry.

Synergistic corrosion inhibition effects of the non-hazardous cerium nitrate and tannic acid polyphenolic molecules on the surface of mild-steel in chloride-containing solution: Detailed surface and electrochemical explorations

The generation of novel inhibitive molecules that can compete with harmful conventional chromium ones has remained a serious challenge in corrosion engineering. The present study aims to develop a newfangled natural compound to hinder the aggressive consequences of steel corrosion. To this end, the synergistic effects of the eco-friendly cerium nitrate on the corrosion retardation ability of the tannic acid (TAA) were examined for the metal specimens subjected to the saline (NaCl containing) solution. The adsorption of the TAA molecules and Ce:TAA complex on the metal substrate was evaluated by FTIR analysis. The surface properties of the samples were analyzed via SEM, UV–Vis spectroscopy, GIXRD, AFM, contact angle, and the Raman spectroscopy techniques. The effectiveness of the Ce:TAA mixture on the mild steel (MS) corrosion mitigation was examined through the EIS and polarization techniques. The results showed that the minimum corrosion current density (icorr = 0.54 μA/cm2) and the maximum total resistance (Rt ~ 22 Kohm.cm2) were observed for the samples immersed in the solution containing the Ce:TAA mixture (with the 1:1 mass ratio). The complex formation between the TAA molecules and Fe/Ce cations was proved the surface studies. The contact angle of the steel samples immersed in the saline solution containing Ce:TAA mixtures increased at least threefold. The inhibition efficiencies of the independent Ce and TAA inhibitors in the saline solution was measured around 74–92% and − 16-64%, respectively, while their optimum composition showed more than 86% efficiency all over the immersion time.

Normal and cancer cells response on the thin films based on chitosan and tannic acid

A novel aspect of tissue engineering is the material selective influence on the different cell types. The cell viability is a parameter which determine the cell ability to proliferate in the contact with material. In the experimental study the thin films based on chitosan and tannic acid mixture in ratio 80/20, 50/50 and 20/80 were tested. The surface roughness decreases with increasing tannic acid content. The cell culture was established on the proposed films. In vitro tests were carried out for the different cell lines as MNT-1, SK-MEL-28, Saos-2, HaCaT and BMSC. The result showed the dependence on the material influence on the various cell lines.

The characterization of thin films based on chitosan and tannic acid mixture for potential applications as wound dressings

Abstract Natural polymers can be used to produce materials for biomedical application. In this study, polymeric blends based on chitosan and tannic acid in the form of thin films were obtained. They were characterized for the potential application as wound dressings. Thereby, the thermal stability, maximum tensile strength and water vapor permeability were measured. Moreover, the blood compatibility was determined as the erythrocytes hemolysis rate. The results showed that the addition of tannic acid to chitosan improves the physicochemical properties of the film. The maximum tensile strength and water vapor permeation rate were improved. The hemolysis rate was higher for films with a higher amount of tannic acid than for those containing pure chitosan, however, the value was below 5%, which allows for the medical application of the proposed materials as wound dressings.

A Tannic Acid–Derived N‐, P‐Codoped Carbon‐Supported Iron‐Based Nanocomposite as an Advanced Trifunctional Electrocatalyst for the Overall Water Splitting Cells and Zinc–Air Batteries

AbstractRational design and construction of a multifunctional electrocatalyst featuring with high efficiency and low cost is fundamentally important to realize new energy technologies. Herein, a trifunctional electrocatalyst composed of FePx nanoparticles and Fe–N–C moiety supported on the N‐, P‐codoped carbon (NPC) is masterly synthesized by a facile one‐pot pyrolysis of the mixture of tannic acid, ferrous chloride, and sodium hydrogen phosphate. The synergy of each component in the FePx/Fe–N–C/NPC catalyst renders high catalytic activities and excellent durability toward both oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). The electrocatalytic performance and practicability of the robust FePx/Fe–N–C/NPC catalyst are further investigated under the practical operation conditions. Particularly, the overall water splitting cell assembled by the FePx/Fe–N–C/NPC catalyst only requires a voltage of 1.58 V to output the benchmark current density of 10 mA cm−2, which is superior to that of IrO2–Pt/C‐based cell. Moreover, the FePx/Fe–N–C/NPC‐based zinc–air batteries deliver high round‐trip efficiency and remarkable cycling stability, much better than that of Pt/C–IrO2 pair‐based batteries. This work offers a new strategy to design and synthesize highly effective multifunctional electrocatalysts using cheaper tannic acid derived carbon as support applied in electrochemical energy devices.

The role of tannic acid and sodium citrate in the synthesis of silver nanoparticles

We describe herein the significance of a sodium citrate and tannic acid mixture in the synthesis of spherical silver nanoparticles (AgNPs). Monodisperse AgNPs were synthesized via reduction of silver nitrate using a mixture of two chemical agents: sodium citrate and tannic acid. The shape, size and size distribution of silver particles were determined by UV–Vis spectroscopy, dynamic light scattering (DLS) and scanning transmission electron microscopy (STEM). Special attention is given to understanding and experimentally confirming the exact role of the reagents (sodium citrate and tannic acid present in the reaction mixture) in AgNP synthesis. The oxidation and reduction potentials of silver, tannic acid and sodium citrate in their mixtures were determined using cyclic voltammetry. Possible structures of tannic acid and its adducts with citric acid were investigated in aqueous solution by performing computer simulations in conjunction with the semi-empirical PM7 method. The lowest energy structures found from the preliminary conformational search are shown, and the strength of the interaction between the two molecules was calculated. The compounds present on the surface of the AgNPs were identified using FT-IR spectroscopy, and the results are compared with the IR spectrum of tannic acid theoretically calculated using PM6 and PM7 methods. The obtained results clearly indicate that the combined use of sodium citrate and tannic acid produces monodisperse spherical AgNPs, as it allows control of the nucleation, growth and stabilization of the synthesis process.Graphical abstractᅟ

Post-embedding Mammalian Tissue for Immunoelectron Microscopy: A Standardized Procedure Based on Heat-Induced Antigen Retrieval.

We describe a standardized method of fixation, antigen retrieval, and image contrasting for post-embedding immunoelectron microscopy. Tissues are fixed with formaldehyde solutions containing Ca(2+) and Mg(2+) ions at pH 7.4 and then at pH 8.5. After dehydration with dimethylformamide, the specimens are embedded in LR-White resin. For antigen retrieval, ultrathin sections are heated in 0.5 M Tris-HCl, pH 9.0, for 1-2 h at 95 °C. After immunogold labeling, the sections are treated with a mixture of tannic acid and glutaraldehyde, with OsO4 solution, and then double-stained with uranyl acetate and lead citrate. The standardized method yields strong and reproducible immunoreactions for many antigens showing excellent image contrast without destruction of fine structures.

Solvent effect on the anodic oxidation of tannic acids: EPR/UV–Vis spectroelectrochemical and DFT theoretical study

Cyclic voltammetry of tannic acid mixture (TAM) in water, dimethylsulfoxide (DMSO), and acetonitrile (ACN) indicates the highest oxidation potential for TAM in ACN, followed by the slightly lowered potential in DMSO and a strongly shifted oxidation potential in water solutions, confirming its pH-dependent redox behavior. In situ EPR and UV–Vis spectroelectrochemical experiments were performed to follow the oxidation reactions of TAM in protic and aprotic media. The formation of an unstable semiquinone anion radical formed upon anodic oxidation of TAM was proved by in situ EPR spectroelectrochemistry both in DMSO and water solutions. The quantum chemical calculations of the model pyrogallol derivatives and tannic acid molecules with four and ten galloyl moieties estimated the role of the spatial hydrogen bonds on the proton affinities and suggested the possible interpretation of experimentally detected redox and spectroelectrochemical behaviors.

Facile synthesis of novel Ni(ii)-based metal–organic coordination polymernanoparticle/reduced graphene oxide nanocomposites and their application for highly sensitive and selective nonenzymatic glucose sensing

The present paper reports on the facile preparation of novel Ni(II)-based metal-organic coordination polymer nanoparticle/reduced graphene oxide (NiCPNP/rGO) nanocomposites for the first time. The formation of the nanocomposites occurs in a single step, carried out by hydrothermal treatment of the mixture of tannic acid functioned graphene oxide and NiCl(2) aqueous solution in N,N-dimethylformamide. It is found that the NiCPNP/rGO nanocomposite-modified electrode shows high electrocatalytic activity for glucose oxidation in alkaline medium. This nonenzymatic glucose sensor exhibits high selectivity toward glucose and the linear range and limit of detection are estimated to be from 0.01 to 8.75 mM (r: 0.997) and 0.14 μM with a signal-to-noise ratio of 3, respectively. The application of this glucose sensor in human blood serum has also been demonstrated successfully.

Gelatin tannate reduces the proinflammatory effects of lipopolysaccharide in human intestinal epithelial cells

BackgroundGelatin tannate is a mixture of tannic acid and gelatin. Tannic acid has astringent properties, due to its capacity to form protein–macromolecular complexes, as well as antibacterial and antioxidant properties. However, little is known about its anti-inflammatory properties.PurposeTo evaluate the anti-inflammatory activity of gelatin tannate by quantifying the suppression of key molecules produced during inflammatory events in lipopolysaccharide (LPS)-stimulated human intestinal cells.MethodsIntercellular adhesion molecule-1 (ICAM-1) expression was determined by Western blot analysis; interleukin-8 (IL-8) and tumor necrosis factor-α (TNF-α) concentrations were measured by enzyme-linked immunosorbent assays in Caco-2 cells 24 hours after treatment with LPS (1 μg/mL) in presence of different concentrations of gelatin tannate.ResultsICAM-1 is induced on a wide variety of cells by inflammatory stimuli such as LPS. Our results have shown gelatin tannate as a potent inhibitor of ICAM-1 expression in LPS-stimulated Caco-2 cells. IL-8 and TNF-α are important inflammatory mediators, recruiting neutrophils and T-lymphocytes. Together with LPS, adding gelatin tannate at different concentrations induced a dose-dependent inhibition of IL-8 and TNF-α released by Caco-2 cells.ConclusionThese results suggest that gelatin tannate exerts anti-inflammatory effects by inhibiting the specific cytokines and adhesion molecules involved in several inflammatory disorders.

Studies on Development on Methodology for Extraction of Phenolic Compound from Hydro-Alcoholic Wood Extracts

This article presents results on the liquid-liquid extraction studies for the separation of tannic acid from aqueous and hydro-alcoholic medium. These liquid-liquid extraction studies aim to investigate the suitable hydrophobic solvent or solvents combination and to optimize the extraction conditions for the quantitative separation of tannic acid from aqueous and hydro-alcoholic feed. A mixture of hexanol and octanol is found to be most suitable for the quantitative extraction of tannic acid from aqueous feed solution. One hour equilibration time was enough to reach equilibrium. With increase in tannic acid concentration from 10 mg · L−1 to 900 mg · L−1 in the feed solution, the extraction of tannic acid was found to be decreasing. The concentration of ethanol plays an important role in controlling the solubility of feed in hydrophobic solvent. The suitable solvent combination was tested for the selectivity for individual polyphenol from a mixture of tannic acid and Epi-catechin and it was found that a combination of hexanol and octanol was good for tannic acid extraction whereas decanol was more selective for Epi-catechin extraction.

Nanoscale Increases in CD2-CD48-mediated Intermembrane Spacing Decrease Adhesion and Reorganize the Immunological Synapse

The relationship between intermembrane spacing, adhesion efficiency, and lateral organization of adhesion receptors has not been established for any adhesion system. We have utilized the CD2 ligand CD48 with two (wild type CD48 (CD48-WT)), four (CD48-CD2), or five (CD48-CD22) Ig-like domains. CD48-WT was 10-fold more efficient in mediating adhesion than CD48-CD2 or CD48-CD22. Electron tomography of contact areas with planar bilayers demonstrated average intermembrane spacing of 12.8 nm with CD48-WT, 14.7 nm with CD48-CD2, and 15.6 nm with CD48-CD22. Both CD48-CD2 and CD48-CD22 chimeras segregated completely from CD48-WT in mixed contact areas. In contrast, CD48-CD2 and CD48-CD22 co-localized when mixed contacts were formed. Confocal imaging of immunological synapses formed between primary T lymphocytes and Chinese hamster ovary cells presenting major histocompatibility complex-peptide complexes, and different forms of CD48 demonstrated that CD48-CD2 and CD48-CD22 induce an eccentric CD2/T cell antigen receptor cluster. We propose that this reorganization of the immunological synapse sequesters the T cell antigen receptor in a location where it cannot interact with its ligand and dramatically reduces T cell sensitivity.

Intraalveolar bubbles and bubble films: III. Vulnerability and preservation in the laboratory.

Having confirmed (Scarpelli et al. 1996. Anat. Rec. 244:344-357 and 246:245-270) the discovery of intraalveolar bubbles and films as the normal anatomical infrastructure of aerated alveoli at all ages, we now address three questions. Why have these structures been so elusive? Visible in fresh lungs from the in vivo state, can they be preserved by known laboratory methods? Can they be preserved intact for study in tissue sections? Lungs of adult rabbits and pups were examined in thorax directly from the in vivo state to confirm normal bubbles both at functional residual capacity and at maximal volume; other lungs were permitted to deflate naturally to minimal volume. The fate of bubbles in situ (either intact, transected, or diced lung tissue) and of isolated bubbles was assessed (1) during conventional histopreparative processing, (2) during inflation-deflation after degassing, (3) after drying in air, (4) during and after quick freezing in liquid N2, and (5) after preservation in fixed and stained tissue sections prepared by a new double-impregnation procedure in which glutaraldehyde-fixed tissue was preembedded in agar, dehydrated and clarified chemically, embedded in paraffin, sectioned, and stained. Control studies included both blocking of bubble formation by rinsing the air spaces with Tween 20 prior to double impregnation and preparation of normal tissue without preembedding in agar. (1) Each of the following procedures in conventional processing dislocated and disrupted bubbles and films: osmium tetroxide and glutaraldehyde:formaldehyde:tannic acid mixture fixation; chemical dehydration (70-100% ethanol) and clarification (xylene and acetone); and embedding in paraffin or epoxy resin. Transection and dicing of the tissue aggravated the untoward effects. In contrast, bubbles and films remained stable in either glutaraldehyde or formaldehyde, which, however, did not protect against the other agents. (2) Degassing destroyed all bubbles as expected; however, bubbles and films re-formed immediately with reinflation. (3) Topography of fixed bubbles and films was retained after air drying. The dry polygonal configuration reverted to spherical-oval either in saline solution or in 50% ethanol, whereas vulnerability to upgraded ethanol concentrations was unchanged. (4) Normal topography and shape appeared to be retained during quick freezing and after thawing. (5) Intraalveolar and intraductal bubbles and films were preserved and photographed in sections from tissue prepared by the double-impregnation procedure; they were not seen either when bubble formation had been blocked (double-impregnation procedure) or when preembedding in agar had been omitted. (1) Whether or not fixed in glutaraldehyde or formaldehyde, preservation of intraalveolar and intraductal bubbles and films is not to be expected in tissue prepared by conventional histopreparative procedures, whereas product artifacts may be expected from bubble rupture in situ. (2) Degassing cannot be recommended for studies of alveolar structure-function interrelations because all natural bubbles are disrupted in the process, and bubble re-formation may not parallel their "natural history" in vivo. (3) Compared with glutaraldehyde or formaldehyde fixation, air drying offers no added protection against the untoward effects of conventional processing. (4) Quick-frozen tissue is equally at risk. (5) A new double-impregnation procedure does preserve bubbles and films during processing, sectioning, and staining.

Lamellar bodies of mouse taste buds after fixation with tannic acid.

Circumvallate papillae of adult dd-mice were fixed in a mixture of tannic acid, glutaraldehyde, and paraformaldehyde, postosmicated, embedded in Epon, and observed under an electron microscope. An accumulation of globular electron-dense bodies (70-500 nm in diameter) was found in the apical cytoplasm of the three types of slender taste bud cells, and among the microvilli in the taste pores. High-resolution micrographs of these bodies revealed a lamellar structure with a period of 5 nm, which is characteristic of phospholipids. It is likely that tannic acid in the fixative reacts with the choline base of phospholipids to form an insoluble complex of lamellar bodies. In vivo, the phospholipids may be diffusely distributed throughout the apical cytoplasm and released into the taste pores, and may thus act as a surfactant to promote the solubility of sapid materials, which facilitates their adsorption to the membranes of microvilli of taste bud cells.

Two different secretion mechanisms in the inner ear's interdental cells

Fixation with a mixture of tannic acid and glutaraldehyde reveals a darkly stained substance in the intercellular clefts between juxtapposed interdental cells, where it is included by pynocytotic vesicles. Over the interdental cells, similar-sized vesicles (35–45 nm) are present in clear spaces of the amorphous layer of the limbal portion of the tectorial membrane. Some images suggest that they may be secreted through small disruptions of the membrane of the interdental cells' microvilli. In addition, a TA-unstained, amorphous material is present inside both basal ducts and apical cavities of the interdental cells, thus suggesting another secretory route from the basal region of the interdental cells towards either the endolymph, or the tectorial membrane. These two secretion processes coexist in a single interdental complex, and the two secretion products may be involved in the turnover of the adult tectorial membrane and/or the secretion of some component of the endolymph.

Mutagenicity tests with gallic and tannic acid in the Salmonella/mammalian microsome assay.

Gallic acid, tannic acid mixture and a purified fraction of tannic acid were evaluated for possible mutagenic activity in three strains of Salmonella typhimurium, TA98, TA100, and TA1535. These chemicals were not mutagenic either before or after activation with rat and woodchuck microsomal and cytosolic enzymes. However, tannic acid mixture and tannic acid fraction both gave a significantly (p = 0.05) dose-related reduction in the number of the revertant colonies, compared to the normal spontaneous revertants with no apparent toxic effects in the background lawn. With an agar diffusion assay, the chemicals exhibited toxic effects at 5000 micrograms/disc.

The use of tannic acid fixation for the electron microscope visualization of fluorochrome-labelled antibodies attached to cell surface antigens

Tannic acid as a prefixative for EM purposes was introduced by Futaesaku et al. (1972). The fixative creates conditions for enhancing electron density of different protein materials. By using a mixture of tannic acid and glutaraldehyde as prefixative, followed by a routine procedure of postfixation (OsO 4) and poststaining (uranylacetate and lead citrate), membrane bound antibodies not conjugated with electron dense markers are made visible under the electron microscope.

Extramembranous particles in tubular myelin from rat lung

Tubular myelin is one morphologic form taken by extracellular pulmonary surfactant. We used electron microscopy after fixation in a mixture of tannic acid and glutaraldehyde followed by osmication to examine tubular myelin fixed in situ , isolated from lavage fluid by isopyknic centrifugation in sucrose gradients, and prepared in vitro from isolated lamellar bodies by the addition of 5 m M Ca 2+ . In each case, the bilayered membranes of tubular myelin were seen as parallel arrays or as a lattice with a spacing of approximately 5 nm. The use of tannic acid produced good visualization of rows of rod-like particles 5 nm in diamter and 14–16 nm in length. The particles were regularly spaced at intervals of 14–16 nm in rows along the angels formed by intersecting membranes. Particles on opposite sides of the bilayer were in register. Since these particles were observed on tubular myelin formed by the addition of calcium to purified lamellar bodies as well as on tubular myelin formed in vivo , they appear to form from material prepackaged in the lamellar bodies of the type II cells. We suggest that these particles are protein and are involved in the formation or maintenance of the structure of tubular myelin.