Two-Component Hydrogels Built from Chinese Herbal Medicine-Derived Glycyrrhizic Acid and Puerarin: Assembly Mechanism, Self-Healing Properties, and Selective Antibacterial Activity

Abstract

Chinese herbal medicine has offered a great treasure for discovering intrinsically bioactive low molecular weight gelators (LMWGs). Herein, the two-component hydrogels comprising glycyrrhizic acid (GA) and puerarin (PUE), the primary bioactive components, respectively, from herbs Glycyrrhiza uralensis Fisch and Pueraria lobata are successfully prepared. Combined spectroscopic characterizations reveal that hydrogen bonds are formed between GA and PUE molecules, which further drives the growth of nanofiber assemblies into gel networks. Importantly, micromorphological observation by scanning electron microscopy (SEM), synchrotron small-angle X-ray scattering (SAXS), and molecular dynamic simulation suggest that a coassembly pathway is involved in the gelling process. Such two-component hydrogels exhibit good injectable, self-healing, and adhesive properties. Interestingly, the mixed GA-PUE hydrogels demonstrate a more efficient and selective antibacterial activity toward S. aureus instead of E. coli, and a PUE ratio-dependent antibacterial activity toward S. aureus is also observed. Our work highlights that CHM-derived LMWGs can provide a scaffold for developing multicomponent hydrogels, which may afford novel and distinct properties compared with their individual ones. It is assumed that more multicomponent supramolecular hydrogels derived from CHM would appear to better address the challenges, particularly in the biomedical field.