Polyphenol Tannic Acid Research Articles

Arsenic-Induced Inflammatory Response via ROS-Dependent Activation of ERK/NF-kB Signaling Pathways: Protective Role of Natural Polyphenol Tannic Acid.

Arsenic (As), a highly toxic metalloid, is present throughout our environment as a result of both natural and human-related activities. Furthermore, As exposure could lead to a persistent inflammatory response, which may facilitate the pathogenesis of several diseases in various organs. This study was performed to investigate the As-induced inflammatory response and the underlying molecular mechanisms invitro. Further, the anti-inflammatory effects of a natural dietary polyphenol tannic acid (TA) were also explored. In human normal bronchial (BEAS-2B), adenocarcinoma alveolar basal (A549), and murine macrophages (J774) cell lines, a trivalent form of As (as As3+) exposure markedly induced the expression of various pro-inflammatory mediators (cytokines and chemokines). Additionally, it was found that As3+ exposure induced reactive oxygen species (ROS) generation and activation of the nuclear factor-kappa B (NF-kB) p65 and extracellular signal-regulated kinase (ERK)1/2 pathways in BEAS-2B cells. As expected, the blockade of either ERK1/2 (PD98059) or NF-kB p65 (IMD0354), or both pathways attenuated As3+-induced pro-inflammatory mediators release. Interestingly, pre-treatment with ROS inhibitor N-acetylcysteine (NAC) attenuated activation of ERK/NF-kB pathways, suggesting that ROS have a critical role in pathway's activation and subsequent inflammatory response. Further, TA pre-treatment effectively attenuated As3+-induced inflammatory response by suppressing ROS production and ERK/NF-kB signaling pathways activation. Therefore, this study provides scientific evidence for the anti-inflammatory activities of TA and the underlying molecular mechanisms.

Controlling vaccine kinetics using tannic acid for enhanced humoral immunity.

Despite the success of global vaccination campaigns, vaccine access in low-resource settings is an ongoing challenge. Subunit vaccines are a well-established and clinically scalable intervention, yet they have achieved limited success for poorly immunogenic antigens such as those associated with SARS-CoV-2. Delivery strategies that promote gradual release of subunit vaccines from the injection site offer the potential to improve humoral immunity by enhancing lymph node exposure, however, clinical implementation of this strategy is challenging due to poor scalability and high costs. Here, we propose an approach that uses the polyphenol tannic acid (TA) as a simple and inexpensive strategy to enhance tissue residence of vaccines and subsequent humoral immunity. We show that TA mediates supramolecular interactions between vaccine components and tissue at the subcutaneous injection site to promote extended retention of protein antigens for over one week. In addition to enhancing the magnitude and duration of vaccine drainage to the lymph nodes, inclusion of TA improved accumulation of activated, antigen-laden monocyte-derived dendritic cells (moDCs), promoting long-lasting humoral immunity against the receptor-binding domain (RBD) of SARS-CoV-2 and variants of concern. This system, termed TAPER (Tannic Acid-Promoted Enhanced Retention) provides various translational advantages including one-pot synthesis, scalability, low cost, and modularity, towards realization of effective and accessible subunit vaccines.

Synergistic photothermal enhancement of the antibacterial activity of fibroin hydrogel by dual-directional crosslink strategy for efficient solar steam generation

Silk fibroin (SF) has attracted wide attention due to its excellent biocompatibility and versatile adjustability. The regeneration and reutilization of silk fibroin can efficiently utilize waste cocoons and silk. However, the regenerated SF hydrogels suffer from inadequate mechanical properties and lack inherent antibacterial capabilities, limiting their application in seawater desalination. This study achieved a novel hydrogel (STS@Fe) with photothermal antimicrobial activity, good mechanical property, and excellent durability using a green dual-directional crosslink and meso-reconstruction strategy. The metal-phenolic networks (MPN) were synthesized utilizing the natural plant polyphenol tannic acid (TA) and Fe3O4 nanoparticles. This research incorporated MPN into dissolved and regenerated silk fibroin and sodium alginate solution, enhanced mechanical properties through cryogenic salt precipitation, and prepared STS@Fe hydrogel. The inherent photothermal properties of Fe3O4 nanoparticles and TA complex, coupled with their synergistic effect under near-infrared radiation, can confer excellent photothermal-enhanced antibacterial activity to the fibroin hydrogel. The tensile strength of STS@Fe hydrogel is enhanced 31 times than that of traditional fibroin hydrogel, and its evaporation rate is 4.77 times higher than that of pure water evaporation. The hydrogel has an efficient seawater desalination rate and outstanding antibacterial properties in real seawater conditions. Moreover, The STS@Fe shows effective treatment capabilities for dyeing wastewater and oily saline water.

GSH responsive AuNRs@TFF nanotheranostic for NIR-II photoacoustic imaging-guided CDT/PTT synergistic cancer therapy

Gold nanorods (AuNRs) are important photothermal therapeutic agents; however, a single therapy does not achieve satisfactory outcomes, and the synthesis process often leads to the adsorption of cetyltrimethylammonium bromide on the surface of AuNRs, which reduces its biocompatibility. Natural polyphenols are abundant in natural plants and have good biocompatibility. The metal-polyphenol network is formed by the coordination of metal ions and polyphenols, which has good drug loading, surface adhesion, and biocompatibility. In this study, the metal-polyphenol network structure formed by a transition metal (iron) and natural polyphenol tannic acid was used to modify the surface of gold nanorods (AuNRs@TF). Additionally, the surfaces of AuNRs were modified using the targeted functional molecule mercapto folic acid (AuNRs@TFF). The constructed composite nanomaterials AuNRs@TFF has good biocompatibility and tumor targeting ability. Tannic acid‑iron degrades in the tumor microenvironment and releases iron ions that catalyze the Fenton reaction, thereby facilitating chemodynamic therapy. The good photo-thermal ability of AuNRs generate good photoacoustic signals to facilitate photoacoustic imaging mediation and enhances photothermal and chemodynamic therapy performance. This study expands on the application of AuNRs in the field of nanomedicine. The simple and effective design of AuNRs@TFF provides a strategy for the development of synergistic therapeutic agents for photothermal therapy and chemodynamic therapy.

Protein-tannin interactions towards fabricating flame-retardant, UV-resistance, antibacterial and mechanical-reinforced PA66 fabric

The “Protein-polyphenol interactions” is a hot research topic in the field of interaction between biological macromolecules. Strong interactions between biomass polyphenolic tannins and proteins can be generated through covalent and non-covalent bonds. Inspired by this, keratin (Ker) and oxidized tannin (TA) was co-deposited on polyamide 66 (PA66) fabric to fabricate OTA/Ker coated PA66 fabric (PA66@OTA/Ker), which was then chelated with Fe3+ to prepare fire resistance and anti-dripping PA66 fabric (PA66@OTA/Ker@Fe). The results showed that the total heat release rate (THR), peak heat release rate (pHRR) and total smoke production (TSP) of PA66@OTA/Ker@Fe were reduced by 51 %, 57 % and 52 %, respectively. PA66@OTA/Ker@Fe had a residue char of 21.6 % at 800 °C under N2 atmosphere. In addition, the LOI of PA66@OTA/Ker@Fe increased from 20.5 % of the control sample to 28.5 % and reached a UL-94 V-0 rating. Besides, PA66@OTA/Ker@Fe exhibited excellent UV resistance, good mechanical and anti-bacterial properties. This work provides an eco-friendly strategy for developing multifunctional PA66 fabrics.

Corilagin alleviated intestinal ischemia-reperfusion injury by modulating endoplasmic reticulum stress via bonding with Bip

BackgroundIntestinal ischemia-reperfusion (II/R) injury is a common clinical emergency with high morbidity and mortality. Given the absence of efficacious prophylactic and therapeutic interventions and specific drugs, sustained efforts are essential to develop new targeted drugs. Corilagin, a naturally polyphenolic tannic acid widespread in longan, rambutan and many other edible economic crops with medicinal properties in China, is of interest due to its multiple bioactivities, including the potential to mitigate II/R injuries. Nevertheless, a clear understanding of its molecular targets and the intricate mechanisms against II/R injury remains obscure and requires further elucidation. ObjectiveThis study aimed to investigate corilagin's pharmacological impact and molecular mechanism for II/R injury. MethodsAn animal II/R model was established by clamping superior mesenteric artery (SMA), and the therapeutic efficacy of corilagin against II/R was evaluated by biochemical and pathological analysis. Next, integrated transcriptomic and proteomic analyses was performed to identify key targets. Moreover, endoplasmic reticulum stress (ERS) damage was respectively observed by transmission electron microscope (TEM), immunohistochemistry, TUNEL, flow cytometry and western blotting (WB). Finally, molecular docking, molecular dynamics (MD) simulation, cellular thermal shift assay (CETSA) and drug affinity responsive target stability (DARTS) assays were utilized to assess the interaction between corilagin and binding immunoglobulin protein (Bip, Grp78 or Hspa5), and co-IP assay was conducted to investigate the interaction between Bip and its substrate proteins. ResultsCorilagin exhibited robust protection against II/R injuries, effectively alleviating intestinal tissue damage and oxidative stress induced by II/R. The modulation of ERS as a potential regulatory mechanism was investigated through an integrated transcriptomic and proteomic analysis, identifying Bip as a key target contributing to corilagin's protective effects. Further experimental evidence using molecular docking, MD simulation, CETSA, and DARTS assays confirmed the potentially direct interaction of corilagin with Bip. This interaction promoted the ubiquitin-dependent degradation of the Bip-substrate complex, thereby suppressing ERS-related signalling pathways, including the IRE1 branch, PERK branch, and ATF6 branch, to alleviate tissue damage. ConclusionThis study confirmed that corilagin could selectively bind to Bip, facilitating its ubiquitin-dependent recognition and degradation, thereby inhibiting severe endoplasmic reticulum stress signalling and alleviating II/R injury. A detailed mechanistic insight into the action mode of corilagin had been proposed, supporting its potential usage as an ERS inhibitor.

A pH-sensitive, renewable invisible orthodontic aligners coating manipulates antibacterial and in situ remineralization functions to combat enamel demineralization.

During invisalign treatment, as salivary proteins or glycoproteins fill the space between the teeth and the aligners, they can easily adhere to the teeth, forming an acquired cellular film on which bacteria are highly susceptible to colonizing, which in turn leads to the development of enamel white staining lesions (WSLs), one of the major complications of orthodontic treatment. Inhibiting the activity of cariogenic bacteria while promoting the remineralization of demineralized enamel is the key to preventing and treating WSLs. Currently, the drug commonly used in clinical practice for the treatment of WSLs is silver diamine fluoride, which, although it has both antimicrobial and remineralizing effects, suffers from problems such as pulpal irritation and tooth discoloration. In this study, based on the principle of coordination chemistry, copper ions and plant polyphenol tannins were assembled on invisible orthodontic aligners to form a metal-phenol network coating (TA-Cu MPNs), and zwitterionic sulfonamethyldopamine was introduced for bionic mineralization to obtain the multifunctional coating TA-Cu MPNs@ZDS@CaP (TZC). The coating exhibits acid-responsive release of Ca2+ and PO4 3-, and the decomposed CaP layer can be regenerated by a simple dipping method. The TZC coating strongly inhibits common cariogenic bacteria and their biofilms. In addition, the results of the in vitro mineralization experiment show that TZC-coated invisible orthodontic aligner treatment of demineralized enamel has significant remineralization effects. It is worth mentioning that the constructed coating has a durable antibacterial effect and can meet the service cycle of invisible orthodontic aligners. This study provides theoretical and experimental bases for the prevention or treatment of WSLs in invisible orthodontic treatment.

Polyphenolic tannin-based polyelectrolyte multilayers on poly(vinyl chloride) for biocompatible and antiadhesive coatings with antimicrobial properties

Poly(vinyl chloride) (PVC), a synthetic polymer, is used in various biomedical applications, particularly in the development of catheters. PVC-based catheters are engineered for blood-contacting applications. However, these materials lack antimicrobial properties, resulting in bacterial proliferation and subsequent infections. To overcome this disadvantage, blood-compatible and antimicrobial polyphenolic tannin-based surface coatings, known as polyelectrolyte multilayers (PEMs), were adsorbed onto PVC for the first time. PEMs were created on reduced PVC (Red-PVC) or oxidized PVC (Oxi-PVC) substrates using the layer-by-layer (LbL) approach. An amino-functionalized polyphenolic tannin derivative (TN-NH2), commercially known as Tanfloc, and an unmodified polyphenolic tannin (TN), commercially known as Weibull black, were assembled (15 layers) on Oxi-PVC or Red-PVC at pH 5.0. PVC substrates and PEMs were characterized through atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and water contact angle (WCA) measurements. The PEMs showed enhanced wettability compared to the unmodified PVC, with water contact angles ranging from 42° to 38°. The root mean square (Rq) roughness of the PEMs ranged from 64.5 nm to 74.1 nm, while the unmodified PVC surface displayed a relatively smooth surface with a roughness of 5.4 nm. Stability tests demonstrated that the PEMs maintained their integrity in phosphate buffer (pH 7.4) over seven days at 37°C. The obtained PEMs were not toxic to human fibroblasts and human erythrocytes. The Live/Dead antimicrobial assay results indicated that the PEMs possessed biocidal activity against Pseudomonas aeruginosa (P. aeruginosa) and antiadhesive capacity toward Staphylococcus aureus (S. aureus) and P. aeruginosa after 24 h of incubation. Cytocompatible and antimicrobial tannin-based PEMs on modified PVC surfaces can represent a significant advancement in mitigating bacterial infections associated with PVC-based catheters.

Dendritic Cell Immune Modulation via Polyphenol Membrane Coatings.

Cellular hitchhiking is an emerging strategy for the in vivo control of adoptively transferred immune cells. Hitchhiking approaches are primarily mediated by adhesion of nano and microparticles to the cell membrane, which conveys an ability to modulate transferred cells via local drug delivery. Although T cell therapies employing this strategy have progressed into the clinic, phagocytic cells including dendritic cells (DCs) are much more challenging to engineer. DC vaccines hold great potential for a spectrum of diseases, and the combination drug delivery is an attractive strategy to manipulate their function and overcome in vivo plasticity. However, DCs are not compatible with current hitchhiking approaches due to their broad phagocytic capacity. In this work, we developed and validated META (membrane engineering using tannic acid) to enable DC cellular hitchhiking for the first time. META employs the polyphenol tannic acid (TA) to facilitate supramolecular assembly of protein drug cargoes on the cell membrane, enabling the creation of cell surface-bound formulations for local drug delivery to carrier DCs. We optimized META formulations to incorporate and release protein cargoes with varying physical properties alone and in combination and to preserve DC viability and critical functions such as migration. We further show that META loaded with either a pro- or anti-inflammatory cargo can influence the carrier cell phenotype, thus demonstrating the flexibility of the approach for applications from cancer to autoimmune disease. Overall, this approach illustrates a new platform for the local control of phagocytic immune cells as a next step to advance DC therapies in the clinic.

Mussel-inspired antimicrobial hydrogel with cellulose nanocrystals/tannic acid modified silver nanoparticles for enhanced calvarial bone regeneration

Bacterial infection is a serious challenge in the treatment of open bone defects, and reliance on antibiotic therapy may contribute to the emergence of drug-resistant bacteria. To solve this problem, this study developed a mineralized hydrogel (PVA-Ag-PHA) with excellent antibacterial properties and osteogenic capabilities. Silver nanoparticles (CNC/TA@AgNPs) were greenly synthesized using natural macromolecular cellulose nanocrystals (CNC) and plant polyphenolic tannins (TA) as stabilizers and reducing agents respectively, and then introduced into polyvinyl alcohol (PVA) and polydopamine-modified hydroxyapatite (PDA@HAP) hydrogel. The experimental results indicate that the PVA-Ag-PHA hydrogel, benefiting from the excellent antibacterial properties of CNC/TA@AgNPs, can not only eliminate Staphylococcus aureus and Escherichia coli, but also maintain a sustained sterile environment. At the same time, the HAP modified by PDA is uniformly dispersed within the hydrogel, thus releasing and maintaining stable concentrations of Ca2+ and PO43− ions in the local environment. The porous structure of the hydrogel with excellent biocompatibility creates a suitable bioactive environment that facilitates cell adhesion and bone regeneration. The experimental results in the rat critical-sized calvarial defect model indicate that the PVA-Ag-PHA hydrogel can effectively accelerate the bone healing process. Thus, this mussel-inspired hydrogel with antibacterial properties provides a feasible solution for the repair of open bone defects, demonstrating the considerable potential for diverse applications in bone repair.

Investigation of morphology and volume phase transition of supramacromolecular microgels by NMR spectroscopy and quartz crystal microbalance

AbstractMicrogels have a wide range of applications, from catalysis to biomedical applications such as drug delivery in dispersion, or as surface‐attached materials to improve the biocompatibility of implants or as anti‐fouling coatings. The first aim of this work is to understand the morphology of the supramacromolecular, tannic acid (TA) crosslinked microgels using two‐dimensional 1H NMR spectroscopy, and relaxometry. The second aim is to study the volume phase transition (VPT) of TA‐crosslinked microgels with different crosslinker densities in dispersion using NMR. In this context, 1H high‐resolution NMR spectroscopy is used in combination with the two‐state model and the Boltzmann sigmoidal function to determine thermodynamic quantities of the VPT, such as temperature (Tt), width of transition (ΔTt), and change in entropy (ΔS). Third, surface‐deposited microgels are characterized in terms of their VPT using a quartz crystal microbalance (QCM‐D) to study the properties of these microgels for applications where they are used as coatings. Finally, the Tt of microgels supramolecular crosslinked with TA are compared with microgels covalently crosslinked with N,N′‐methylenebisacrylamide (BIS) in dispersion, using NMR, and deposited on a surface, using QCM‐D. For this purpose temperature‐responsive poly(N‐vinylcaprolactam) and poly(N‐isopropylacrylamide) microgels crosslinked with the plant‐derived polyphenol TA or BIS are used.

Bleomycin-induced modulations of PARP 1 activity, NAD+ and PARG content in rat lung nuclei

Bleomycin-induced lung pathology in rodents is a well recognized animal model widely used for evaluation of new therapeutic approaches in treatment of lung inflammation and fibrotic diseases. It is documented that poly(ADP-ribose)polymerase 1 activity has a significant role in development of inflammatory processes in the heart, liver and brain. Herein, we used biochemical and immunochemical methods for estimation of poly(ADP-ribose)polymerase 1 (PARP 1) activity, NAD+ and poly(ADP-ribose)glycohydrolase (PARG) protein content in rat lung nuclei during the inflammatory phase in a bleomycin-induced one-hit rat model. To evaluate the influence of bleomycin – induced alterations in DNA structure on regulation of poly(ADP-ribose)polymerase 1 activation pathways, we isolated DNA from nuclei of lung tissues in the phase of acute lung inflammation induced by bleomycin, and DNA melting profiles were investigated. In the present study we investigated whether naturally occurring water-soluble polyphenol tannic acid with widely accepted anti-fibrotic and anti-inflammatory effects can influence poly(ADP-ribose)polymerase 1 activity, NAD+ and poly(ADP-ribose)glycohydrolase protein content in nuclear fraction isolated from rat lung tissues in a bleomycin-induced acute lung injury model. It was demonstrated that NAD+ level and poly(ADP-ribose)glycohydrolase protein content decreased in rat lung nuclei during the inflammatory phase in the bleomycin-induced acute lung injury model. Treatment of rats with tannic acid enhanced the effects displayed by bleomycin in lung nuclei, thus indicating synergistic interaction with the drug in the field covering PARP 1 activity, poly(ADP-ribose)glycohydrolase (PARG) protein and NAD+ content in lung nuclei. We observed PARP 1 inhibition in nuclei of lung tissue during the inflammatory phase in the bleomycin-induced acute lung injury rat model, which could be coupled with the drop of NAD+ level in nuclei. In the present study we highlighted that bleomycin (BLM) can induce DNA destabilization in lung nuclei. It was proposed that bleomycin-induced modulations in DNA structure could hamper PARP 1 binding with DNA and down-regulate the enzyme activating pathway in lung nuclei. The role of poly(ADP-ribose)glycohydrolase depletion in lung nuclei and sequential accumulation of poly(ADP-ribose)polymers in lung cells, which triggers their destruction and tissues damage, was proposed. It is suggested that in the light of synergistic interaction between bleomycin and tannic acid (TA) the anti-inflammatory role of tannic acid should be repurposed.

Enhanced bacteriostasis and osseointegrative properties of SiRNA-modified polyetheretherketone surface for implant applications.

Polyetheretherketone (PEEK), bearing an elastic modulus that effectively simulates the innate properties of natural bone, has come into the spotlight as a promising bone substitute material. Nonetheless, the biologically inert nature of PEEK, combined with its insubstantial osseointegration and sterilization capabilities, pose constraints on its clinical application in the realm of implants. RNA interference (RNAi), an effective technique used for gene expression regulation, has begun to be applied in implant surface modification. Herein, siCKIP-1 is securely affixed to the surface of PEEK implants, aided by an antibacterial polyphenol tannic acid (pTAN) coatings, enhancing physiologic osseointegration and inhibiting bacterial infection. This method breakthrough not merely facilitates the convenience, but also multifaceted PEEK implants' refinements. The modified PEEK implants have impressive biocompatibility coupled with a noteworthy degree of antibacterial properties. Meanwhile, modified PEEK implants improved osteogenic differentiation of rat bone mesenchymal stem cells (rBMSCs) and demonstrated excellent osteointegrative properties in rat femur implantation models. Therefore, identifying a new implant material with excellent biocompatibility and biomechanical properties is essential.

Mussel-inspired adhesive and anti-swelling hydrogels for underwater strain sensing.

The application of hydrogels in an underwater environment is limited due to their swelling behavior and the existence of a hydration layer. In this study, a hydrogel based on poly(sulfobetaine methacrylate) (PSBMA), tannic acid (TA) and montmorillonite (MMT) was prepared with excellent anti-swelling properties and underwater self-adhesion properties. The PSBMA hydrogel has excellent anti-swelling properties due to the strong electrostatic interaction between charged groups of PSBMA chains. Inspired by marine mussels, tannic acid modified montmorillonite (TA@MMT) was introduced. Natural polyphenol tannic acid, as a catechol donor, provides a large number of catechol groups for hydrogels. Montmorillonite acts as the physical cross-linking point of PSBMA chains through electrostatic interaction to improve the cohesion of the hydrogel. By combining the adhesion mechanism of zwitterions and catechol, the hydrogel maintains adhesion in air and underwater environments. In addition, a strain sensor was prepared based on the PSBMA/TA@MMT hydrogel, which can closely fit the human skin and stably monitor different movements in air and in underwater environments. Through a Bluetooth communication system, long-distance information transmission can be achieved. Therefore, the PSBMA/TA@MMT hydrogel broadens the application prospect of wearable devices in the underwater environment.

MicroRNA-195-5p mediates arsenic-induced cytotoxicity in human lung epithelial cells: Beneficial role of plant-derived tannic acid

Arsenic (As), a highly toxic metalloid, which causes environmental lung diseases and affects millions of people worldwide. Respiratory epithelial cells are essential for maintaining lung homeostasis, aberrant epithelial damage and death due to exposure to a wide range of environmental pollutants, which are considered to be the initial trigger for many pulmonary diseases. Accumulating evidence has shown that microRNAs (miRNAs) appear to be important players in various normal physiological and pathological processes. Therefore, the present study was carried out to examine the cytotoxic effects of a trivalent form of As (As3+) in normal human bronchial (BEAS-2B) and adenocarcinoma alveolar basal (A549) epithelial cells and the role of miR-195-5p. Further, we also explored the protective effects of a natural dietary polyphenol tannic acid (TA). As3+ (1 μM) treatment in BEAS-2B cells for 24 h induced cytotoxicity by decreasing the cell viability, mitochondrial membrane potential (ΔΨm) and inducing reactive oxygen species (ROS) generation, lipid peroxidation (LPO), cell cycle arrest, and apoptosis, which was associated with a significantly higher level of miR-195-5p expression compared with vehicle control. Forced expression of miR-195-5p alone suppressed cell survival, ΔΨm, regulated cell cycle distribution and induced ROS generation in BEAS-2B cells. As expected, miR-195-5p inhibition effectively rescued BEAS-2B cells from As3+-mediated toxicity, confirming the involvement of miR-195-5p in the cytotoxic effects of As3+. Further, TA pre-treatment expressively alleviated As3+-induced toxicity by suppressing ROS production, miR-195-5p expression, and increasing ΔΨm. These in vitro results indicate that miR-195-5p may be useful as a therapeutic target for treating As3+ toxicity.

Construction of core@double-shell structured energetic composites with simultaneously enhanced thermal stability and safety performance

The poor thermal stability and high sensitivity severely hinder the practical application of hexanitrohexaazaisowurtzitane (CL-20). Herein, a kind of novel core@double-shell CL-20 based energetic composites were fabricated to address the above issues. The coordination complexes which consist of natural polyphenol tannic acid (TA) and FeIII were chosen to construct the inner shell, while the graphene sheets were used to build the outer shell. The resulting CL-20/TA-FeIII/graphene composites exhibited simultaneously improved thermal stability and safety performance with only 1 wt% double-shell content, which should be ascribed to the intense physical encapsulation effect from inner shell combined with the desensitization effect of carbon nano-materials from outer shell. The phase transition (ε to γ) temperature increased from 173.70 °C of pure CL-20 to 191.87 °C of CL-20/TA-FeIII/graphene composites. Meanwhile, the characteristic drop height (H50) dramatically increased from 14.7 cm of pure CL-20 to 112.8 cm of CL-20/TA-FeIII/graphene composites, indicating much superior safety performance after the construction of the double-shell structure. In general, this work has provided an effective and versatile strategy to conquer the thermal stability and safety issues of CL-20 and contributes to the future application of high energy density energetic materials.

Magnetic phosphazene porous organic polymer for efficient and selective recovery of rare earth elements from acidic wastewater

Efficient recovery of rare earth elements (REEs) from secondary resources is highly recommended to meet industrial production demand and maximize resource utilization. Herein, a magnetic porous organic polymer, termed MTAP, was developed by choosing natural polyphenol tannic acid as a monomer and hexachlorocyclotriphosphazene as a crosslinker. The integration of magnetic nanoparticles further enhanced its advantages since it can be rapidly isolated using an external magnetic field, simplifying the overall operation. Batch adsorption experimental results showed that MTAP can quickly capture REEs including Ce, Nd, Eu, and Gd, achieving the adsorption equilibrium just in 2 min. Furthermore, the adsorption isotherms exhibited an excellent fit with the Langmuir model with the maximum adsorption capacities ranging from 145.5 to 164.2 mg/g at 25 °C. What’s more, MTAP was successfully applied to recycle REEs in industrial wastewater with high recovery efficiencies. These characteristics including low cost, easy preparation, rapid adsorption kinetics, and high adsorption capacities highlight the outstanding application prospects of MTAP for the recovery of REEs.

On-Chip Fabrication of Colloidal Suprastructures by Assembly and Supramolecular Interlinking of Microgels.

In this report, a versatile method is demonstrated to create colloidal suprastructures by assembly and supramolecular interlinking of microgels using droplet-based microfluidics. The behavior of the microgels is systematically investigated to evaluate the influence of their concentration on their distribution between the continuous, the droplet phase, and the interface. At low concentrations, microgels are mainly localized at the water-oil interface whereas an excess of microgels results, following the complete coverage of the water-oil interface, in their distribution in the continuous phase. To stabilize the colloidal suprastructure, on-chip gelation is introduced by adding natural polyphenol tannic acid (TA) in the water phase. TA forms interparticle linking between the poly(N-vinylcaprolactam) (PVCL) microgels by supramolecular interactions. The combination of supramolecular interlinking with the variation of the microgel concentration in microfluidic droplets enables on-chip fabrication of defined colloidal suprastructures with morphologies ranging from colloidosomes to colloidal supraballs. The obtained supracolloidal structures exhibit a pH-responsive behavior with a disintegration at alkaline conditions within a scale of seconds. The destabilization process results from the deprotonation of phenolic groups and destruction of hydrogen bonds with PVCL chains at higher pH.

Development of turn-on fluorescent sensor based on green emissive carnosine-modified tannic acid carbon dots for the selective detection of ascorbic acid

Ascorbic acid (AA) is an indispensable biological antioxidant with anti-aging potential in neurological disorders such as Parkinson’s and Alzheimer’s. Its abnormal concentrations in physiological fluids like human serum can lead to neurological complications. In this study, a turn-on fluorescent sensor was developed using dipeptide (i.e., carnosine) modification of the polyphenolic tannic acid (TA) carbon dots (CDs) (TATA-CDs) for AA detection. Blue-fluorescent TATA-CDs were synthesized using the hydrothermal treatment of the TA and ethylene glycol-bis(β-aminoethyl ether)-N,N,N′,N′-tetraacetic acid (EGTA) as a nitrogen (N) dopant. TATA-CDs were functionalized with carnosine (TATA-Car CDs) using a facile stirring reaction. Their morphological and optical properties were studied via TEM, XRD, UV–Vis, and fluorescence spectroscopy. TATA-Car CDs displayed green fluorescence with excitation and emission wavelength maxima of 400 and 509 nm, respectively. These novel CDs are responsible for the selective turn-on fluorescence sensing of AA (0 to 15 nM) when mixed with copper (Cu2+) ions and deliver a low detection limit of 1.34 nM. The practicality and feasibility of TATA-Car CDs were investigated in human serum samples. From this perspective, the proposed fluorescent sensor is more suitable for the real-time monitoring of AA in different neurological disorders.

Tannic acid-assisted fabrication of antibacterial sodium alginate-based gel beads for the multifunctional adsorption of heavy metal ions and dyes

The existence of heavy metals and dyes seriously affects the ecological environment and human safety. Antibacterial adsorption materials with the broad-spectrum removal of multiple pollutants are urgently required for water remediation. Herein, a sustainable and antibacterial sodium alginate (SA) gel bead adsorbent with honeycomb cellular architecture is developed by the biomimetic deposition polyphenolic tannic acid (TA) induced grafting diethylenetriamine (DETA) under mild conditions for efficient removal of Cr(VI) and dyes. Taking advantage of the catechol surface chemistry, TA occurring rapid polymerization with DETA monomers not only enhances the water resistance and thermal stability of the gel bead, but also introduces abundant polyphenolic functional groups and active adsorption sites. The multifunctional gel bead showed outstanding antibacterial activity against S. aureus (sterilization rates: 83.8 %) and E. coli (sterilization rates: 99.5 %). The maximum adsorption capacity of gel bead for Cr(VI) was 163.9 mg/g. Moreover, the removal efficiency of the gel bead for dyes of Safranine T and Rhodamine B was 89.5 % (maximum adsorption capacity: 537 mg/g) and 76.7 % (maximum adsorption capacity: 460.2 mg/g), respectively, indicating its excellent broad-spectrum adsorption performance for multiple pollutants. Therefore, TA-assisted fabrication of SA-based gel bead with excellent antibacterial property is a promising multifunctional adsorption material for practical water remediation.