tannic acid

Overview

Tannic acid is a plant-derived polyphenolic compound widely used in biomaterials, food science, and drug delivery research because of its strong multivalent binding capacity. Chemically, it can interact with proteins, polysaccharides, metal ions, and other macromolecules through hydrogen bonding, hydrophobic interactions, and coordination chemistry. These properties make tannic acid a versatile cross-linker and structure-directing agent in hydrogels, films, emulsions, coatings, and nanoparticle systems.

In biomedical contexts, tannic acid is often studied less as a conventional drug target and more as a functional component that modulates material structure and bioactivity. Recent work has used it to improve mechanical strength, adhesion, freeze-thaw stability, antioxidant behavior, antibacterial performance, and controlled release. It has also been incorporated into metal-phenolic networks and polymer assemblies for applications ranging from tissue engineering and wound-related materials to antiviral shielding and cancer-selective redox systems.

Focus of Latest Publications

Recent publications have repeatedly used tannic acid as a cross-linker, stabilizer, or coordinating polyphenol in complex biomaterial systems. In multilayered biopolymer films built from carboxymethylcellulose, casein, and zein, tannic acid was included as a cross-linker to study interfacial adhesion by colloidal-probe atomic force microscopy, with the broader goal of developing biodegradable packaging. This places tannic acid in the context of improving cohesion between polysaccharide and protein layers.

In food and emulsion systems, tannic acid was used alongside other polyphenols such as gallic acid and proanthocyanidins to form egg white protein–polyphenol–pullulan ternary complexes, which were then applied to high internal phase emulsions to enhance freeze-thaw stability. A related study on soy glycinin–gum arabic complex coacervates used tannic acid crosslinking, with dextran acting as a structure stabilizer, to fabricate colon-targeted microcapsules and examine effects on gut microbiota. Another food-related study embedded tannic acid in water-in-oil high internal phase emulsions to reduce the oral sensation of astringency associated with tannic acid itself or Rosa roxburghii juice.

Tannic acid also appeared in multiple hydrogel and coating systems. A smart multinet-work hydrogel containing guar gum, polyvinyl alcohol, gelatin, collagen, tannic acid, and a manganese phosphate/chitosan organo-inorganic complex was developed to promote osteoblastic proliferation. Another conductive hydrogel combined poly(vinyl alcohol), acrylic acid, gelatin, tannic acid, quaternary ammonium chitosan, and acetylene black to achieve high strength, freeze resistance, stability, and electrical conductivity for flexible wearable sensors. In a separate ROS-responsive hydrogel, tannic acid cross-linked phenylboronic acid-grafted hyaluronic acid through dynamic boronic ester bonds, enabling on-demand release of bio-nanoselenium under high reactive oxygen species conditions relevant to UVB-induced skin photodamage.

Several studies focused on tannic acid as part of metal-phenolic or coordination assemblies. A carrier-free nanoplatform composed of apigenin, tannic acid, and Cu2+ ions was synthesized through oxidative-mediated coordination assembly for synergistic chemo-photodynamic-photothermal therapy. Another study used tannic acid–FeIII metal polyphenol networks to coat gallic acid-loaded ovalbumin/chitosan nanoparticles, then embedded them in gelatin hydrogel to create a sustained-release antibacterial system for prefabricated meat preservation. Similarly, tannic acid was used to functionalize a chitosan-agarose-gelatin blend through complexation with Cu2+, Sr2+, or dual Cu2+/Sr2+ systems, highlighting its role in tuning structure-driven bioactivity.

Tannic acid was also used in packaging and preservation materials. One study developed tannic acid one-step induced carboxymethyl chitosan–sodium alginate Pickering emulsion composite coatings with tea tree oil for strawberry preservation. Another incorporated tannic acid into a starch-tannin biocomposite with TiO2 nanoparticles to improve UV shielding and eliminate reactive oxygen species, supporting bio-safe sunscreen applications. In these systems, tannic acid contributed to antioxidant protection and material stabilization.

Beyond materials science, tannic acid was investigated in biologically oriented systems. In a food-derived probiotic extracellular vesicle platform for inflammatory bowel disease, tannic acid was combined with chitosan to support a synergistic therapeutic strategy. In antiviral delivery research, tannic acid was used in sequential assembly with adeno-associated virus and phenylboronic acid-modified block copolymers to shield the virus from neutralizing antibodies. In cancer-related redox therapy, tannic acid was reported to reduce Fe3+ back to Fe2+, sustaining an autocatalytic Fenton cycle and continuous hydroxyl radical generation. Tannic acid was also identified as a natural RORγ ligand by fluorescence polarization, with submicromolar binding affinity reported in that assay.

Overall, these studies portray tannic acid as a multifunctional polyphenol that can cross-link biomacromolecules, coordinate metal ions, modulate redox chemistry, and alter interfacial or mechanical properties. Its recurring use across packaging, hydrogels, emulsions, antiviral systems, and therapeutic nanoplatforms reflects its broad utility in biomedical materials research.

Key Publications

• Jun Self-assembled nanoparticles of epigallocatechin gallate and tannic acid against triple-negative breast cancer via mediating mitochondrial damage. (Nanotechnology, 2026, PMID 42263713): "To address these limitations, we developed self-assembled nanoparticles composed of EGCG and tannic acid (TA), stabilized by appropriate excipients, to form EGCG-TA nanoparticles (ET-NPs)."
• Jun Interfacial Adhesion in Multilayered Biopolymer Films Measured by Colloidal-Probe Atomic Force Microscopy─Toward Biodegradable Packaging. (Langmuir : the ACS journal of surfaces and colloids, 2026, PMID 42244204): "The films were constructed from polysaccharides, specifically carboxymethylcellulose (CMC), and proteins, casein and zein, assembled with and without tannic acid (TA) as a cross-linker."
• Jun Egg white protein-polyphenol-pullulan complexes: Structural characterization and application in high freeze-thaw stability high internal phase emulsions. (Food chemistry, 2026, PMID 41932022): "In this study, egg white protein (EWP)-polyphenol-pullulan ternary complexes were constructed using proanthocyanidins (PC), gallic acid (GA), and tannic acid (TA) to enhance the freeze-thaw stability of HIPEs."
• Jun Development of soy glycinin-gum arabic complex coacervates: Fabrication of colon-targeted microcapsules and their effect on gut microbiota. (Food chemistry, 2026, PMID 41967403): "The structure was further fixed by tannic acid crosslinking in the presence of dextran which acted as structure stabilizer."
• Jun Advanced guar gum/polyvinyl alcohol/CS-MnP smart hydrogel for promoting osteoblastic proliferation. (Biomedical materials (Bristol, England), 2026, PMID 42214427): "a smart multi-network hydrogel (HD hydrogel) composed of guar gum, polyvinyl alcohol, gelatin, collagen, tannic acid, and manganese phosphate/chitosan organo-inorganic complex (CS-MnP) was developed"
• Jun Fine-tuned phenylboronic acid polymer assembly with tannic acid enables adeno-associated virus to evade and suppress neutralizing antibody responses. (Journal of controlled release : official journal of the Controlled Release Society, 2026, PMID 41864581): "we developed an AAV-loaded ternary complex through the sequential assembly of AAV, tannic acid (TA), and phenylboronic acid (PBA)-modified block copolymers, protecting AAV from NAbs by polymer shielding."
• Jun NIR Light Activated Polyphenol Driven Carrier-Free Self-Assembled Nanoparticles for Synergistic Chemo-PDT-PTT. (Langmuir : the ACS journal of surfaces and colloids, 2026, PMID 42133860): "Herein, we report a carrier-free polyphenol-metal coordinated nanoplatform composed of apigenin, tannic acid, and Cu2+ ions (AT-Cu NPs), synthesized through an oxidative-mediated coordination assembly."
• Jun A sustained-release antibacterial gelatin hydrogel based on metal-phenolic networks for long-term preservation of prefabricated meat. (Food chemistry, 2026, PMID 41921443): "In this study, tannic acid -FeIII metal polyphenol network-coated gallic acid -loaded ovalbumin/chitosan nanoparticles with adhesion and sustainable antibacterial properties were prepared and embedded into the gelatin hydrogel to elongate the shelf life of prefabricated meat."
• May Tannic acid one-step induced carboxymethyl chitosan‑sodium alginate-Pickering emulsions multifunctional composite coatings for efficient preservation of strawberries. (Food chemistry, 2026, PMID 41865516): "A multifunctional packaging for strawberries, composed of carboxymethyl chitosan, sodium alginate, tannic acid, and tea tree oil, effectively delays deterioration."
• May Fabrication of water-in-oil high internal phase emulsions containing astringent compounds for enhanced oral sensation. (Food & function, 2026, PMID 42065544): "This study aimed to mitigate the sensation of astringency from tannic acid (TA) or Rosa roxburghii Tratt juice (RRTJ) by incorporating them within the internal aqueous phase of water-in-oil high internal phase emulsions (W/O HIPEs)."