Bioadhesion design of hydrogels: adhesion strategies and evaluation methods for biological interfaces

A hydrogel with bioadhesive function has high water content, inherent flexibility, adjustable mechanical strength, adequate biocompatibility, and a wide range of application prospects in the field of biomedicine. However, achieving reversible and robust adhesion between the hydrogel and the biological interface remains a challenge, including slow adhesive formation, weak adhesion, low biocompatibility, poor mechanical matching with tissues, and the lack of a benign detachment that can be triggered. Bioadhesive hydrogels adhere to distinct biological tissues and are used in biomedicine through the interaction between interfaces. The adhesion mechanism is usually a combination of multiple interactions in which one interaction is dominant. This article summarizes the preparation of bioadhesive hydrogels, the characteristics of biological interfaces, the methods of enhancing adhesion, and measuring the adhesion of hydrogels. These will assist researchers in developing adhesion strategies and accurately measuring adhesive forces according to contrasting biological interfaces.