Tannic Acid Complexes Research Articles

Iron-polyphenol nanomaterial removes fluoride and methylene blue dye from water and promotes plant growth

Iron-Polyphenols are attractive as adsorbents as polyphenols are abundant in plants and tend to form high-surface-area nanoparticles with metal. However, reports on the large-scale synthesis and adsorption properties are rather limited. We are reporting a multi-gram scale synthesis of a nanostructured material from tannic acid and iron(II) salt. Tannic acid (TA) is a plant polyphenol available in abundant quantities. Analysis and spectroscopic studies of the material confirm the composition as a Fe(III) complex of TA (Fe: TA ~ 9:1) with 25% of iron is in the divalent state. The material has a relatively high surface area (99.6 m2/g). It adsorbs both anionic fluoride and cationic methylene blue (MB) from aqueous solutions. It adsorbs 66% fluoride from contaminated natural water at pH ~7 (C0 4.4 mg/L, dose 3 g/L). It removes 99% methylene blue (MB) dye from an aqueous solution at pH 7 (C0 150 mg/L, dose 4 g/L). The equilibrium study and salt addition experiments suggest that the fluoride removal depends on surface charge and binding with iron. MB can be desorbed using salts of cations with a higher charge. Several reports showed that materials from plant sources could be harmful to plant growth, thereby limiting the use of the adsorbent. We found that tannic acid alone stunts the growth of Mung bean (Vigna radiata) plants, but plants did show significant growth when grown with the material reported here (shoot, 155%, root 200%, twice daily 1 mL of 1 mg/mL).

Anti‐PD‐L1 DNAzyme Loaded Photothermal Mn2+/Fe3+ Hybrid Metal‐Phenolic Networks for Cyclically Amplified Tumor Ferroptosis‐Immunotherapy (Adv. Healthcare Mater. 8/2022)

Tumor Therapy In article number 2102315 by Wenhu Zhou and co-workers, a metal-phenolic network (MPN) nanoplatform with all-active components is constructed via coordination between tannic acid (TA) and metal ion complex of Fe3+/Mn2+, through which a PD-L1 inhibiting DNAzyme (DZ) is loaded. With external laser irradiation, PTT is initiated to synergize with ferroptosis for enhanced ICD, and the combination of DZ-mediated PD-L1 suppression results in a cyclically amplified tumor ferroptosis-immunotherapy.

Wheat starch-tannic acid complexes modulate physicochemical and rheological properties of wheat starch and its digestibility

In this study, the interactions of wheat starch (WS) and tannic acid (TA) were investigated for their gelatinization, pasting, structural, rheological properties and digestibility of wheat starch. TA was either complexed with starch (WS-TA complexes) or mixed with starch (WS-TA mixtures) right before the characterization of its properties. The increase of melting enthalpy and temperature range (Tpeak - Tonset) associated with melting of amylose-lipid complex and the increase in the X-ray diffraction peak at 2θ = 20° possibly indicated the formation of inclusion types of complexes. The appearance of an endothermic transition at 130–160 °C indicated the formation of non-inclusion types of complexes. Non-inclusion type of complexes were mostly formed by co-gelatinization of WS-TA mixtures, while inclusion complexes would be mostly formed by complexation of TA with ungelatinized starch. TA in mixtures increased G′ and viscosity and decreased frequency dependency of the moduli, thus producing a stronger gel. TA in complexes decreased G′ and viscosity at low TA%, thus producing a weak gel, but increased gel strength at high TA%. The storage moduli G′ increased depending on the amount of TA involved in non-inclusion complexes. The formation of complexes between WS and TA largely slowed down the digestibility of gelatinized starch. The insights gained in this study provide opportunities to modulate starch techno-functional properties and digestibility in processing of starchy food.

High internal phase Pickering emulsions stabilized by tannic acid-ovalbumin complexes: Interfacial property and stability

While protein-stabilized high internal phase Pickering emulsions (HIPEs) have demonstrated promising potential for various applications in food, their poor interfacial stability remains as a major challenge to overcome. In this work, tannic acid (TA) was used to increase the stability of ovalbumin (OVA)-stabilized HIPEs. The binding clusters between OVA and TA were hypothesized by the molecular docking simulation, and the interfacial properties of OVA and TA complexes (OVA-TA) were investigated by interfacial tension and three-phase contact angle. The characteristics of HIPEs under different pHs were studied by static light scattering and confocal laser scanning microscopy (CLSM), as well as rheology. The results showed that there were some specific clusters in OVA and TA which may form hydrogen bonds and hydrophobic interactions. The wettability of OVA was significantly improved by TA, resulting in greater interfacial stability at the oil-water interface. Compared with OVA-stabilized HIPEs (O-HIPEs), OVA-TA-stabilized HIPEs (OT-HIPEs) had narrower size distribution, more compact droplet structure and denser gel network to resist droplet aggregation. Especially at pH 4.0, OT-HIPEs exhibited stronger gel network and higher viscosity than at other pH values, because of smaller electrostatic repulsion between OVA and TA, and easier crosslinking on the oil-water interface. In addition, the viscosity of OT-HIPEs was increased after 24 h incubation, indicating the formation of more hydrogen bonds. Meanwhile, OT-HIPEs showed good storage and freeze-thaw stability. Our research findings from this study are expected to provide novel insight on protein-based particles stabilized HIPEs from an interfacial perspective.

Enzyme-Mediated Kinetic Control of Fe3+-Tannic Acid Complexation for Interface Engineering.

Supramolecular self-assembly of Fe3+ and tannic acid (TA) has received great attention in the fields of materials science and interface engineering because of its exceptional surface coating properties. Although advances in coating strategies often suggest that kinetics in the generation of interface-active Fe3+-TA species is deeply involved in the film formation, there is no acceptable elucidation for the coating process. In this work, we developed the enzyme-mediated kinetic control of Fe2+ oxidation to Fe3+ in a Fe2+-TA complex in the iron-gall-ink-revisited coating method. Specifically, hydrogen peroxide, produced in the glucose oxidase (GOx)-catalyzed reaction of d-glucose, accelerated Fe2+ oxidation, and the optimized kinetics profoundly facilitated the film formation to be about 9 times thicker. We also proposed a perspective considering the coating process as nucleation and growth. From this viewpoint, the kinetics in the generation of interface-active Fe3+-TA species should be optimized because it determines whether the interface-active species forms a film on the substrate (i.e., heterogeneous nucleation and film growth) or flocculates in solution (i.e., homogeneous nucleation and particle growth). Moreover, GOx was concomitantly embedded into the Fe3+-TA films with sustained catalytic activities, and the GOx-mediated coating system was delightfully adapted to catalytic single-cell nanoencapsulation.

Enhanced deposition of Fe(III)-tannic acid complex nanofilm by Fe(III)-embedded dextran nanocoating

Nanofilm deposition with Fe(III)-tannic acid (TA) complex serves as a surface nanoengineering technique for a wide variety of substrate materials. However, it has been still elusive to tune the fundamental nanofilm properties, such as thickness and roughness, for a single Fe(III)-TA layer. Here we demonstrate Fe(III)-embedded dextran nanocoating serving as a boosting layer for enhanced deposition of Fe(III)-TA complex nanofilm with higher roughness. The formation of Fe(III)-embedded dextran layer with 0.37 mM FeCl3·6H2O shows maximum three times deposition enhancement of Fe(III)-TA layer in film thickness (ca. 9 nm), compared with the conventional deposition. pH stability tests show that the multilayer structures formed with Fe(III)-TA layers and Fe(III)-embedded dextran layers are highly stable at pH 7.4 but gradually and rapidly degrade at pH 10 and pH 2, respectively. Further surface characterizations disclose that solution pH, correlated with the concentration of Fe(III) source (FeCl3·6H2O), is the major factor governing the deposition enhancement effect: more than 1.85 mM FeCl3·6H2O makes significantly acidic chemical environments hampering the further deposition of Fe(III)-TA nanofilms. The experimental findings herein provide clues for deeper understanding of metal-polyphenol complex nanofilm deposition as well as contribute to the future development of biocompatible nanocoating utilizing promising combinations of polysaccharides and polyphenols.

Resveratrol-β-Lactoglobulin Composite Nanocoating by Layer-by-Layer Assembly with Fe(III)-Tannic Acid Complex.

Resveratrol (3,4',5-trihydroxystilbene) is beneficial to human health due to its diverse biological activities including its anti-inflammatory and anti-oxidative effects as confirmed by pharmacokinetic tests. Despite these clinical merits, resveratrol's limited hydrosolubility and chemical vulnerability remain challenging with regard to developing a controlled delivery system with enhanced bioavailability. In this work, we report a resveratrol-β-lactoglobulin (R-BLG) composite nanocoating through a layer-by-layer assembly with Fe(III)-tannic acid nanofilms. The R-BLG composite nanocoating can be formed in planar and particulate substrates, showing excellent film stability under a broad range of pH values and against enzymatic digestion during a weeklong incubation. We envision that the proteinaceous nanocoating herein could be combined with existing pharmaceutical carrier materials (e. g., microcapsules and nanoparticles) to realize advanced drug delivery systems with an expanded repertoire of hydrophobic drugs.

Complexation of tannic acid with polyoxypropylene diamine in water and application for the preparation of hierarchically structured functional surfaces

We rationalize that a water-soluble low molecular weight polyoxypropylene diamine (i.e., Jeffamine® D400 polyetheramine), capable of various types of noncovalent molecular interactions through its amine and propylene oxide groups, presents a simple yet versatile opportunity to form complexes with natural polyphenol of tannic acid (TA) and be exploited to engineer functional materials and surfaces. By investigating TA-D400 complexation behaviors in water, we demonstrate that mixing weakly acidic TA and neutral D400 solutions of stock concentrations above 1.0 mg/mL allowed easy formation of colloidally stable TA-D400 complexes. Such complexes were characterized as cationic nanoparticles of typical hydrodynamic diameters less than 300 nm. Mixing ratios were found to be less of an influencer on complexation. The TA-D400 intermolecular complexation was shown to be driven primarily by hydrophobic interaction in conjunction with ionic association. A simple immersion process can induce the formation of substrate-independent, hierarchically structured, and highly hydrophilic surfaces because of adsorption of TA-D400 complexes. Such functional surfaces not only can potentially modulate cell-material interactions shown by our brief in vitro fibroblast cell culture study, but also are feasible for in situ facile reduction of HAuCl4 to achieve integration of gold nanoparticles for function enrichment. This TA-D400 system adds a new option to the toolbox of polyphenol-mediated green technologies for surface engineering.

Targeting multiple mediators of sepsis using multifunctional tannic acid-Zn2+-gentamicin nanoparticles

Targeting multiple mediators of sepsis using multifunctional tannic acid-Zn2+-gentamicin nanoparticles

The Relative Contributions of Complexation, Dispersing, and Adsorption of Tannic Acid to the Dissolution of Copper Oxide Nanoparticles

The Relative Contributions of Complexation, Dispersing, and Adsorption of Tannic Acid to the Dissolution of Copper Oxide Nanoparticles

Novel supramolecular network of graphene quantum dots-vitamin B9-iron (III)-tannic acid complex for removal of chromium (VI) and malachite green

The present work is devoted to synthesize graphene quantum dots (GQDs) from waste sugarcane bagasse with average particle size 4.2 nm based on the TEM analysis. The produced GQDs were then aimed to combine with vitamin B9 (folic acid = FA) and Fe3+-tannic acid complex (Fe-TA) for the formation of a novel (GQDs@FA@Fe-TA) supramolecular network with average particle size 37.57 nm and pore diameter 38.35 nm. (GQDs@FA@Fe-TA) was evaluated as a multipurpose nanosorbent for removal of inorganic anionic (Cr(VI)) and organic cationic (malachite green, MG) pollutants from water. Cr(VI) removal was optimized as 99.5% (at pH 3.0 after 5 min), while 94.8% for MG (at pH 6.0 after 30 min). Adsorptions of both pollutants were exothermic and spontaneous and well explained with the pseudo-second order and Langmuir model. (GQDs@FA@Fe-TA) exhibited higher regeneration stability after five consecutive adsorption–desorption cycles (~2.1–4.3% loss). Finally, the potential applications of (GQDs@FA@Fe-TA) for removal of inorganic anionic and organic cationic pollutants from various water samples were 91.2–99.4% and 89.8–92.1% for Cr(VI) and MG, respectively.

Bioinspired adhesive coatings from polyethylenimine and tannic acid complexes exhibiting antifogging, self-cleaning, and antibacterial capabilities

In this work, we develop a simple yet robust method to fabricate a bioinspired adhesive coating based on polyethyleneimine (PEI) and tannic acid (TA) complexes, exhibiting excellent antifogging, self-cleaning, and antibacterial properties. The polyethyleneimine-tannic acid (PEI-TA) complexes coating combined with the bioinspired adhesive property from TA can be effectively and stably coated onto various substrates through a one-step deposition process, and the hydrophilicity of the coated substrates can be significantly enhanced with their water contact angle less than 10°. The bioinspired adhesive coating endows the coated substrates with outstanding antifogging and self-cleaning performance. Moreover, it is found that the PEI-TA coated safety goggles display excellent durability and antifogging capability compared to the commercial antifogging safety goggles and commercial antifogging agents coated safety goggles under 65 ℃ vapor condition for 2 h. Furthermore, the PEI-TA coatings show superior antibacterial activities for Gram-negative Escherichiak coli and Gram-positive Staphylococcus aureus. The antifogging, self-cleaning, and antibacterial coating provides widely potential application prospects in optical and medical devices.

Spraying layer-by-layer assembly of tannin-Fe3+ and polyethyleneimine for antibacterial coating

Tannic acid (TA), as a natural molecule, possesses many excellent properties. It has attracted wide interest in various fields of functional coatings, food, and medicine. A simple method to prepare thick and stable TA-contained coating is required, which may promote practical applications of TA. Here, we proposed a simple and effective method of generating a stable TA-rich coating by spraying layer-by-layer technology. The coating was stabilized basing on the complexation of TA and ferric (Fe3+) ions and poly(ethyleneimine) (PEI). Because both TA and PEI have good antibacterial properties, the (TA-Fe3+/PEI) coating displayed the contact-killing against E. coli. Further, because of the reductive nature of the TA, the coating was able to incorporate nano‑silver particles by reducing silver ions. Consequently, the enhanced antibacterial property was achieved. The (TA-Fe3+/PEI) coating was then spraying coated on the nonwoven mask, showing the potential application in medical protection.

Bioinspired mineral–organic hybridization strategy to produce a green high performance soybean meal based adhesive

Soybean meal-based adhesives have been applied in many fields due to the abundant source and eco-friendly property. However, the preparation of high-performance soybean meal-based adhesives was still challenging. Inspired by the mineral-organic hybridization structure of nacre, hydroxyapatite and tannic acid complex was used as rigid nanofiller and cross-linker to improve the properties of soybean meal adhesives. Tannic acid was bonded with hydroxyapatite through coordination bonds and could promote the hydrogen bond between soybean meal and hydroxyapatite. Owing to enhanced crosslinking density, the wet shear strength of the adhesive increased from 0.66 to 1.70 MPa and the toughness was also clearly improved. The residual ratio increased to 85.8% and the moisture absorption reduced to 16.5%, indicating better water resistance. The high chemical reactivity of catechol and pyrogallol groups on tannic acid endowed the adhesive with better mildew resistance and antibacterial ability. Besides, the addition of hydroxyapatite and tannic acid complex could restrict the heat transfer and quench the oxygen free radicals, which enhanced the flame resistance of the adhesives. This study provided a new strategy for the preparation of green soybean meal-based adhesives with high performance.

Effects of tannic acid on the structure and proteolytic digestion of bovine lactoferrin

Tannic acid (TA) can strongly interact with proteins to improve the stability of protein-based nanoparticles. In the present study, the complexation of TA with bovine lactoferrin (LF) was investigated at pH 6.0. The size and turbidity of the LF-TA complexes did not change significantly until the LF/TA molar ratio was over a critical value of 1:8. Zeta potential of LF-TA was gradually negative as the TA content increased, indicating that there were electrostatic interactions between LF and TA. The circular dichroism (CD) spectroscopy confirmed that TA could further reduce the α-helix and increase the β-sheet content of LF significantly, resulting in a more compact structure of LF. The fluorescence spectra revealed that the interaction between LF and TA caused intramolecular quenching of LF, and the values of Ksv increased with temperature, indicating that static quenching was involved in the interaction between LF and TA. Thermodynamic parameters indicated that the reaction between LF and TA proceed spontaneously, and hydrophobic interactions were the major interaction force. Molecular docking suggested that the binding site of TA and LF was in the inter-leaf region where the two lobes were connected by a spiral. Besides, the proteolytic digestion experiments testified that the addition of TA could reduce the digestibility of LF. Information derived from this work suggests that the addition of TA in LF systems could improve the digestive stability of bio-complex for oral delivery of functional constituents.

Smart responsive nanoplatform via in situ forming disulfiram-copper ion chelation complex for cancer combination chemotherapy

Smart responsive nanomedicines serving as carriers can take advantage of the specific tumor microenvironment (TME) to convert non-toxic drugs into effective anticarcinogens and release chemotherapeutic drugs in situ to improve therapeutic efficiency against tumors without inducing off-target toxicity to surrounding normal tissues/cells. Herein, a pH-responsive metal-organic framework nanoparticle is constructed by encapsulating disulfiram (DSF) and doxorubicin (DOX) into the zeolitic imidazolate framework-8 (ZIF-8) and then coating with copper ion (Cu2+)-tannic acid (TA) complex (denoted as DSF/DOX@ZIF-8@Cu-TA) to achieve enhanced combination chemotherapy. The release of Cu2+ from the outer shell of DSF/DOX@ZIF-8@Cu-TA and the cooperative exposure of DSF and DOX are triggered at multiple stages by mild acidity TME. The accumulation of DSF (non-toxic drugs) and Cu2+ results in the rapid formation of high cytotoxic bis(N, N-diethyl dithiocarbamato)-Cu2+ complexes (CuL2) in situ via DSF and Cu2+ chelating reaction, which accompany the production of ROS via Cu+-based Fenton-like reaction. Besides, the anticancer effect of DOX is augmented by CuL2-modulated ROS-MAPK and NF-κB signal pathways. The constructed DSF/DOX@ZIF-8@Cu-TA present significantly improved therapeutic efficiency as demonstrated both in vitro and in vivo. The strategy of nontoxicity-to-toxicity transitions with the addictive effect of chemotherapeutics provides a promising paradigm to design novel nanoplatforms for synergistic cancer chemotherapy.

Evaluating and improving the reliability of the UV-persulfate method for the determination of TOC/DOC in surface waters

The UV-persulfate oxidation method is widely used for determining the total organic carbon concentration of aqueous samples (denoted for convenience as UVP-TOC). However, for some surface water samples, the measurement of TOC by this method can be unreliable, deviating significantly from the true carbon content. In this study, the performance of the UVP-TOC method has been investigated by comparing the results from the analysis of a variety of aqueous samples that included two kinds of surface water samples and related surface water model substances: bovine serum albumin (BSA), sodium alginate (SA), humic acid (HA), tannic acid (TA), benzoic acid (BA) and citric acid (CA), with those from a high-temperature combustion method (elemental analysis); the latter providing the true carbon content value. By comparing the above data, it was found that the UVP-TOC method significantly underestimated the TOC value of the surface water samples, and it was also found that the model components BSA (protein) and HA (humic substances, HS) had a substantial influence on the TOC underestimation, while the SA (polysaccharide), TA (complex organic molecule) and CA/BA (small molecules) had little effect. The results showed that the agglomeration within and between BSA and HA molecules was an important reason for the inaccurate UVP-TOC values of BSA and HA. A further limitation was that for BSA, surfactants (e.g. sodium dodecylbenzene sulfonate, SDBS) and other surfactant-like substances, foam was formed during the CO2 removal purging process by N2 that seriously interfered with the determination of TOC. The study provides new information and insight into the causes of inaccuracies in the UVP-TOC analysis of surface waters and possible approaches to improve the accuracy.

Designing a high-performance waterborne epoxy coating with passive/active dual self-healing properties by synergistic effect of V2O5@polyaniline-tannic acid inhibitors

Inspirations from nature have led to extensive developments in metal passivation and smart self-healing technologies toward metal corrosion protection. Integration of both intriguing features helps to achieve high-efficiency corrosion inhibition protection. In this study, we designed a novel anticorrosion system composed of waterborne epoxy (WEP) and VPC nanofillers (V2O5 modified by polyaniline and tannic acid complexes) (V2O5@PANI@Fe-TA (3)). Among them, the PANI-modified V2O5 particles have dual roles as oxidation passivation protection and a passive barrier. The tannic acid corrosion inhibitor loaded onto the particles can be released under pH stimulation to provide appropriate activity inhibition function. This dual, synergistic self-healing protection coupled with a robust film barrier was the main reason for the strong anticorrosion properties of the coating system. In a specific experiment, the anticorrosion performance of the composite coatings was verified by electrochemical and salt spray tests. Results revealed that the value of |Z|10mHz for VPC/WEP composite coating was still higher than 108 Ω/cm2 after 80 d of immersion as compared to those of the pure WEP. Interestingly, the VPC/WEPs also exhibited a significant self-healing effect when the corrosive medium reached the metal/coating interface through defects or artificial scratches. This is due to the synergistic protective effect of metal passivation and activity inhibition, which enhanced the anticorrosion properties of the coating system.

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.

Metal-Phenolic network and metal-organic framework composite membrane for lithium ion extraction

To tackle the increased demand of lithium production, the separation of monovalent and divalent cations is crucial for lithium recovery from brine. Recently, metal-organic framework (MOF) has shown great potential in such application due to its tuneable pore size and pore channel chemistry in the sub-atomic scale. Commercialization of ion-selective MOF-based membrane requires the fabrication of MOF thin film on a polymeric support that enables scale-up procedure. Herein, we specifically design a facile method of fabricating zeolitic imidazolate framework (ZIF-8) on a flexible polymeric membrane, using versatile tannic acid and iron complexes (TA-FeIII) as an intermediate layer to promote heterogenous MOF nucleation and growth. The TA-FeIII/ZIF-8 film demonstrated ion selectivity ratio of K+/ Mg2+ (4.49), followed by Na+/ Mg2+ (4.0) and Li+/ Mg2+ (3.87); while the selectivity ratio of Ca2+/ Mg2+ is 1.1. Further investigation suggests that partial dehydration-hydration process plays a role for ion transport mechanism across the TA-FeIII/ZIF-8. However, the separation between monovalent ions remains a difficult challenge due to the trade-off between low dehydration energy of K+ and fast ion transport of dehydrated Li+. This study provides an insight in utilizing the versatile TA-FeIII coating for scale-up growth of MOF thin film for molecular separations.