Photothermal-Triggered Structural Change of Nanofiber Scaffold Integrating with Graded Mineralization to Promote Tendon–Bone Healing

Scaffolds functionalized with graded changes in both fiber alignment and mineral content are more appealing for tendon-bone healing. This study reports the healing of rotator cuff injury using a heterogeneous nanofiber scaffold, which is associated with a structural gradating from aligned to random and an increasing gradient of mineral content in the same orientation. The photothermal-triggered structural change of a nanofiber scaffold followed by graded mineralization is key to constructing such scaffolds. This type of scaffold was found to be biocompatible and provide beneficial contact guidance in the manipulation of tendon-derived stem cell morphologies in vitro. Specifically, tenogenic and osteogenic differentiation of tendon-derived stem cells were simultaneously achieved using the fabricated scaffold. In vivo investigation also showed the improved healing of rabbit rotator cuff injuries based on immunohistochemical analysis and biomechanical investigation that indicates the promising potential of a dual-gradient nanofiber scaffold in clinical tendon-bone healing.Graphical abstractDual-gradient nanofiber scaffold with transitions in both surface structure and mineral content was designed and manufactured to replicate the native interface between tendon and bone to facilitate the tendon-bone healing in a rabbit rotator cuff injury model.