1.Hunan Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health,Hengyang Medical School, University of South China, Hengyang 421001, China
2.College of Biological and Environmental Engineering, Binzhou University,Binzhou 256600, China
Hydrogels are three-dimensional network polymers, which are hydrophilic but insoluble in water. These materials have high water content, good biocompatibility, and strong permeability. Since the properties of hydrogels are highly similar to biological tissues, hydrogels are widely used in biomedical field, such as tissue engineering, drug delivery, and cell culture. However,traditional hydrogels usually exhibit limitations, such as low mechanical strength, easy to damage, and short service life. In recent years,the self-healing hydrogel with the ability to automatically repair damage has been developed with the improvement of molecular design and synthesis technology, which greatly compensates for the defects of traditional hydrogels. Here, this article mainly reviews the research progress of self-healing hydrogels based on dynamic non-covalent bonds and covalent bonds. The methods of constructing self-healing hydrogels by non-covalent bonds (including hydrogen bonding, hydrophobic association, host-guest interaction and ionic interaction) and covalent bonds (including borate bond, imine bond, acylhydrazone bond and disulfide bond) and the application of self-healing hydrogel in the biomedical field are discussed separately. Finally, we briefly summarize the challenges and prospects of self-healing hydrogels, aimed at providing a certain reference for the synthesis and biomedical applications of self-healing hydrogels.