Tannic Acid Physically Cross‐Linked Responsive Hydrogel

Abstract

Tannic acid (TA) is a polyphenol‐rich compound found in many natural plants. There are large numbers of phenolic hydroxyls at the terminal of the TA molecule, being capable of forming hydrogen bonds with hydrogen‐bonding donating polymers such as polyvinylpyrrolidone (PVP) and then engineering a hydrogel network. The reversible switch between phenolic hydroxyls and quinones tuned by pH affords the dynamic nature of the resultant hydrogen bonds. The gels exhibit excellent shear‐thinning and self‐recovery properties. Moreover, the polyphenols can form coordinates with Fe(III) that link different TAs to form a hydrogel network. Hence, adding Fe(III) solution to the TA‐PVP sol can form additional interactions inside the TA‐PVP gel. The easy preparation of the dual‐responsive gels with nontoxic raw materials may allow for its application in the biomedical field.

A Hydrogen‐Bonded Extracellular Matrix‐Mimicking Bactericidal Hydrogel with Radical Scavenging and Hemostatic Function for pH‐Responsive Wound Healing Acceleration

“…Instead, physical entanglement by naturally occurring polymers or materials can be a better option since they are usually cost-effective and biologically friendly, while the fabrication process is rapid, simple, and scalable. [23,24] For example, tannic acid (TA), a plant-derived polyphenol, has been recently attracted high attention for one-pot physical synthesis of hydrogels by numerous hydrogen bonding with other polymers, such as polyvinyl alcohol (PVA), [25] polyvinylpyrrolidone (PVP), [26] carboxylated agarose, [27] and DNA. [28] TA can render intrinsic anti-inflammatory, antioxidant, and antibacterial properties to the hydrogels.…”

Tannic acid-inspired, self-healing, and dual stimuli responsive dynamic hydrogel with potent antibacterial and anti-oxidative properties

“…The pH responsive release of the FITC-BSA from the gel was probably caused by the switch between phenolic hydroxyls and quinones of TA tuned by the environmental pH. 34 TA has a central core of glucose and is rich with phenolic hydroxyl groups (9-10 gallic acid residue), which form strong hydrogen bonds with the BSA molecules. 44 When the solution's pH was adjusted to neutral or slightly basic (7.0-7.4), the phenolic hydroxyl would transfer into quinone groups, which resulted in decreased interaction of TA with the BSA molecule as well as the phenylboronic acid group.…”

“…16 These features have influenced the development of hydrogels containing TA as a key precursor, which simply endows the hydrogels with multifunctional properties that are fit for various biomedical applications. 16,32,34 Besides, the galloyl and catechol groups in TA have redox potential, facilitating the utilization of TA as a green chemistry approach for the preparation of metallic nanoparticles, such as silver and gold nanoparticles. [35][36][37][38] In this work, TA acts with three functions: the reductant, the hydrogel precursor, and the protein binder.…”

Antioxidant Network Based on Sulfonated Polyhydroxyalkanoate and Tannic Acid Derivative

“…Moreover, polyphenols due to their cyclic structure and the presence of a large content of hydroxyl groups are good candidates for the development of stable physical gels and offer the possibility to be easily modifiable through these accessible functions. Tannic acid has already shown the ability to make gels or hydrogels with good mechanical structures by different interactions such as supramolecular interactions by hydrogen bonds [ 45 ], coordination with transition metals [ 46 , 47 ], and a self-assembly method by redox reaction [ 48 , 49 ]. A series of biobased UV-curable antibacterial resins were synthesized through modifying tannic acid with glycidyl methacrylate (GMA) [ 50 ].…”