Gradient Bipolar Nanofiber Scaffolds with a Structure of Biomimetic Tendon-Bone Interface as Rotator Cuff Patches

Due to the special three-dimensional gradient structurefrom thebone to tendon at the tendon-bone interface (TBI), it is difficultto achieve a good therapeutic effect after rotator cuff injury. Biomimetictissue-engineered gradient biphasic fiber patches may be a potentialscaffold for repair. In this study, a gradient bipolar nanofiber scaffoldwith a structure of biomimetic TBI (SPGM) was prepared by continuouslayer-by-layer electrospinning using poly(glycolide-co-& epsilon;-caprolactone), silk fibroin, and mesoporous bioactive glasses.The physicochemical characterization and mechanical test results confirmedthat the SPGM could effectively avoid the stress concentration causedby easy to aggregate components and exhibited significantly matchedmechanical properties. Moreover, SPGM also exhibited higher porosity,larger specific surface area, and suitable pore size for the growthof host cells. Cytocompatibility experiments, immunofluorescence staining,and cell morphology further demonstrated that the bipolar structureof gradient patches could induce rapid proliferation and adhesionof fibroblasts and osteoblasts, respectively. Therefore, this gradientbipolar nanofiber scaffold maybe a reliable candidate for rotatorcuff repair.