A bamboo-derived cellulose "high-speed rail" scaffold with gradient topology and temporal immunomodulation for tendon-bone interface regeneration.

Natural bamboo is an intrinsically aligned cellulose scaffold with hierarchical vascular bundles, longitudinal microchannels, and anisotropic topology, making it a promising natural template for biomedical scaffold engineering. However, its potential for complex interface tissue regeneration remains underexplored. Here, inspired by the native structure of bamboo, we developed a bamboo-derived biomimetic "high-speed rail" platform for tendon-bone interface regeneration. Natural bamboo slices were processed by delignification, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidation, gradient mineralization, and collagen hydrogel integration to construct a scaffold with aligned transport channels and tendon-to-bone gradient topology. The preserved bamboo microchannels served as natural "tracks" for directional fluid transport and cell guidance, while the gradient structure provided spatial cues for regional regeneration. The tendon-like region promoted filamentous actin (F-actin) remodeling, Yes-associated protein (YAP) nuclear translocation, and tenogenic differentiation, whereas the mineralized bone-like region supported bone-side integration. By incorporating tannic acid/carbon nanotube nanocomposites, the scaffold further enabled near-infrared-responsive tannic acid release and temporal immunomodulation. In vivo, this bamboo-derived cellulose scaffold promoted bone regeneration, tendon-like tissue formation, fibrocartilage-like transition reconstruction, and functional recovery. This study presents a sustainable cellulose scaffold strategy for tendon-bone interface regeneration.