Plant‐Inspired Pyrogallol‐Containing Functional Materials

Abstract

Pyrogallol-containing molecules are ubiquitous in the plant kingdom. The chemical synthesis of these molecules remains challenging. Thus, they are obtained via purification from heterogeneous mixtures of plant extracts. Previous studies have focused on their biological roles, such as antioxidants. Additionally, the molecules are used as ink colorants and in tanning processes for leather. Recently, many disciplines have paid attention to adhesiveness of pyrogallol-containing molecules, including the control of interface properties in energy storage/generation and medical devices, as well as the changes in wettability related to membrane technologies. In particular, pyrogallol-containing molecules act as "molecular glues," binding to virtually all biomacromolecules, for example, DNA/RNA, soluble proteins, insoluble extracellular matrices, and peptides. Furthermore, the cohesion of pyrogallol by forming pyrogallol-to-pyrogallol covalent bonds is useful for the preparation of bulk hydrogels and thin films. The content of this review focuses on interactions with biomacromolecules used as molecular glues, used as modifiers in material-independent surface chemistry, and applied as chemical moieties to form covalent linkages to fabricate hydrogels and related biomaterials. Future perspectives include the development of new pyrogallol-containing materials, the understanding of chirality in adhesion, and the improvement of the mechanical stability for applications in various biomedical, energy, and industrial devices. molecules, strategies for surface modifications, and biomedical applications (Figure 1). Based on the timeline of pyrogallol research, we begin by describing the basic physicochemical properties of pyrogallol analogs, focusing on intermolecular interactions with macromolecules. Section 2 introduces the chemical versatility of pyrogallol analogs in macromolecular complexation, and analytical methods for the complexation are explained. Furthermore, the biological functions of pyrogallol analogs, particularly their therapeutic effects on cancers and inflammatory diseases, are explained. Next, surface modification strategies using pyrogallol-containing molecules are explained (Section 3). We discuss pyrogallol-derived formulations for biomedical purposes, ranging from hydrogels to particles (Section 4). Finally, we conclude with an outlook for the further development and implementation of natural pyrogallol analogs and pyrogallol-conjugated synthetic polymers. This review will be helpful for understanding past studies and current progress in pyrogallol-containing molecules research and for predicting future perspectives. Chemical and Structural Analysis of Colloidal ComplexationEarly uses largely involved intermolecular interactions between pyrogallol analogs and proteins. Pyrogallol analog complexations were particularly effective in studies of proline-rich proteins (PRPs)

Particle engineering enabled by polyphenol-mediated supramolecular networks

“…2e), indicating that the pBDT was assembled with the phenolics via noncovalent interactions rather than covalent bonds. Furthermore, all of the obtained particles had a surface zeta potential ranging from −30 to −40 mV in water (Supplementary Table 1), suggesting that the surface was composed primarily of polyphenols 16,23 . Such pBDT-TA particles were stable in solutions of 100 mM sodium dodecyl sulfate (SDS), Tween 20, Triton X-100, NaCl, or urea, but could readily disassemble in organic solvents such as dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), and DMF ( Fig.…”

Polyphenol-Mediated Assembly for Particle Engineering

“…Therefore, polyphenols are widely compatible structural motifs for engineering materials for targeted applications spanning chemistry, materials science, and nanomedicine. 5,6 In the last decade, our group has explored a variety of polyphenol-mediated assemblies for materials engineering (Figure 1). [7][8][9][10][11][12][13][14][15][16][17][18][19] In the present Account, the term "polyphenol" is used to refer to catechol-and gallol-containing aromatic building blocks with functionality common to polyphenols, without distinction between natural polyphenols and their synthetic derivatives.…”

Hydrolyzable vs. Condensed Wood Tannins for Bio-based Antioxidant Coatings: Superior Properties of Quebracho Tannins

“…Tannins occupy a prominent role among natural phenolic compounds due to their remarkable antioxidant, antimicrobial, and anticancer activities [ 1 , 2 , 3 ]. Apart from these biologically relevant properties, these compounds have always been known for their ability to strongly interact with proteins, which has prompted their use in the leather tanning industry [ 4 , 5 ].…”