Advanced hydrogel coatings at tissue repair interfaces: Material design and biomedical applications

Implants are commonly used for tissue repair in clinical medicine. However, the regenerative effect is limited by the mismatch in physical properties and functionality between implant and perienchyma. Hydrogel coatings serve as an ideal “soft interface” between artificial medical devices and biological tissues, leveraging their exceptional hydrophilicity and biomimetic characteristics to play an indispensable role in enhancing the surface properties and functions of biomaterials. This review systematically summarized the fundamental materials science and interfacial engineering strategies underlying hydrogel coatings. Building upon their classification, the review deeply analyzes their intrinsic properties and unique advantages as implant coatings. Subsequently, it highlights state-of-the-art surface fabrication techniques and elucidates how rational functionalization enables the transition of coatings from passive barriers to active regulatory interfaces. Next, the clinical adaptability and therapeutic efficacy of hydrogel coatings are discussed across diverse medical domains. Finally, the article outlines emerging developmental directions for robust theoretical foundation and innovative technical pathways toward intelligent and precision-oriented medical coating systems. The flexible smart hydrogel coating links the tissue to hard device may build up the bridge of the tissue engineering and chemical material design to promote the rapid development of regenerative medicine field.