Adhesive hydrogels for tissue repair: Underlying mechanisms and strategic design

Adhesive hydrogels have emerged as an important class of biomaterials for biomedical applications. Through rational molecular design and controllable synthesis strategies, these materials can mimic both the biochemical and physical characteristics of the extracellular matrix, showing excellent biocompatibility and favorable tissue adaptability. Nonetheless, achieving stable adhesion to biological tissues remains challenging. Tissue surfaces are inherently wet and dynamically changing, which weakens interfacial interactions and compromises adhesion stability. The presence of interfacial water further forms a hydration barrier that limits direct contact between hydrogels and tissues. Therefore, developing effective strategies to achieve robust wet adhesion has become a central focus in this field. In this review, we summarize the fundamental adhesion mechanisms of adhesive hydrogels. Then, we discuss recent strategies for overcoming the interfacial water barrier, and highlight the design principles for balancing the interfacial adhesion with cohesive strength. The integration of multifunctional adhesive hydrogels and their biomedical applications are also introduced. Finally, current challenges and future perspectives for clinical translation are discussed, providing insights for the rational design of next-generation adhesive hydrogel systems.