A review of recent advances in metal ion hydrogels: mechanism, properties and their biological applications

In the past few decades, metal ion hydrogels have made great achievements in various aspects of the biological field. As an ion providing empty orbitals, metal ions are able to coordinately interact with ligands with lone pairs of electrons. The hydrogels formed by the coordination combination of metal ions and other substances had diverse properties and had a wide range of biological applications. In this review, we summarized the research progress of metal ion hydrogels and introduced the formation mechanism of metal ion hydrogels. The effects of the introduction of metal ions on the properties of hydrogels, including responsiveness, self-healing, antibacterial properties, mechanical properties, and conductivity were briefly described. In addition, we also reviewed the biological applications of metal ion hydrogels in tissue engineering, wound healing, drug release, and biosensors. Finally, we summarized the research progress of metal ion hydrogels and looked forward to the development and challenges facing this field.