A carrier-free organometallic hydrogel originated from natural baicalin and Zn2+ with antibacterial and antioxidant efficacy

Organometallic hydrogels are a special kind of hydrogels, in which metal ions are involved in 3D networks and have become one of the pioneering soft material types. Due to its porous microstructure and flexibility, it shows great potential, especially in the biomedical field. The current research mostly uses biological macromolecules such as gelatin, chitosan or polymers as a matrix to prepare gels, with complex preparation process and potential toxicity. Herein, we proposed a carrier-free binary metal-organic small molecule hydrogel formed by self-assembly of natural antibacterial and anti-inflammatory phytochemical baicalin (BA) and Zn2+ (ZnCl2), through non-covalent bonds such as π-π stacking and hydrogen bonding. The organometallic hydrogel has great rheological properties and biological activities. It can inhibit the growth of pathogenic bacteria, reduce the production of ROS, prevent cell damage, and has good biocompatibility. In this study, a carrier-free organometallic hydrogel was successfully prepared, showing great injectability, antibacterial, antioxidant activity and biosafety, and has the potential to be developed into a wound dressing. Most importantly, current study provided a new idea for the self-assembly of organic small molecule ligands and metal ions to prepare hydrogels.