Current progress of self-healing polymers for medical applications in tissue engineering

The research of self-healable polymers intended for medical use has increased in the last 20 years. These materials can self-repair and recover their functionality after damage; thus, they are of significant interest in diverse academic areas, including the biomedical field. In this regard, numerous synthetic and natural polymers are being used to develop self-healing hydrogels for tissue engineering applications, particularly for the restoration of bones, cartilage, skin, and even the central nervous system. These materials possess distinct advantages; for example, natural polymers are usually biocompatible and biodegradable, whereas synthetic polymers could be more suitable when rigid hydrogels with fast kinetics are required. Moreover, the intrinsic reticular matrix of these self-healing systems allows the load of diverse drugs and their controlled release. Remarkably, polymers may be mixed to obtain hydrogels with enhanced mechanical and biological properties. The elaboration of self-healable hydrogels is carried out through either covalent crosslinking or non-covalent crosslinking; the selection of the method depends on many factors, including the required mechanical properties and desired use. Although some articles have reviewed self-healing hydrogels, papers focused on utilizing these systems in tissue engineering are scarce. In this article, we perform a concise description of fabrication methods of self-healing hydrogels and the employed polymers. Furthermore, we provide numerous examples of hydrogels intended for biomedical purposes and discuss their key functional properties. Our main objective was to point out the most recent progress in utilizing self-healing polymers in tissue engineering.