Polyphenol-mediated silk fibroin adhesive integrated with chitosan film for sealing of annulus fibrosus defects

A tannic acid–modified silk fibroin adhesive enables rapid gelation, wet adhesion, and intrinsic self-healing behavior. • Polyphenol-mediated silk fibroin forms a dynamic network via hydrogen bonding and hydrophobic interactions. • The chitosan /silk fibroin-tannic acid patch exhibits strong adhesion and stability on biological and polymeric substrates. • The patch promotes to seal annulus fibrosus defect  in vivo  and preserves disc hydration and biomechanics. Annulus fibrosus defects disrupt the structural integrity and mechanical balance of the intervertebral disc, leading to nucleus pulposus herniation and subsequent nerve compression, which ultimately results in pain and related clinical symptoms. Therefore, developing biocompatible materials capable of effectively sealing annulus fibrosus defects is of great clinical significance for preventing nucleus pulposus extrusion and restoring disc function. In this study, we developed a wet-adhesive patch composed of silk fibroin-tannic acid adhesive integrated with a chitosan film (CS/SF-TA patch) for effective sealing of annulus fibrosus defects. The assembly of the SF-TA adhesive was driven by hydrophobic interactions and hydrogen bonding, enabling rapid gelation, strong wet adhesion, and self-healing capability. The CS/SF-TA patch achieved an interfacial adhesion strength with 71 kPa on wet porcine skin, while exhibiting antioxidative activity. In addition, the patch underwent swelling-mediated integration with surrounding tissues and demonstrates favorable biocompatibility. In vivo studies further showed that the composite patch effectively sealed annulus fibrosus defects, preserved nucleus pulposus hydration, and significantly attenuated disc degeneration. This polyphenol-mediated silk fibroin assembly strategy, combined with a chitosan substrate, provided a versatile platform for robust wet-tissue adhesion and may be extended to a wide range of biomedical applications requiring mechanically support and self-healing adhesive materials. The polyphenol-mediated CS/SF–TA composite patch, assembled through hydrogen bonding and hydrophobic interactions, exhibits robust wet adhesion, antioxidant activity, and excellent biocompatibility, enabling effective sealing of AF defects and preservation of IVD structure and hydration in vivo . Download: Download high-res image (64KB) Download: Download full-size image