Multifunctional Nanofibrous Scaffolds with Angle-Ply Microstructure and Co-Delivery Capacity Promote Partial Repair and Total Replacement of Intervertebral Disc

There is an urgent clinical need for the treatment of annulus fibrosus (AF) impairment caused by intervertebral disc (IVD) degeneration or surgical injury. Although repairing injured AF through tissue engineering is promising, the approach is limited by the complicated angle-ply microstructure, inflammatory microenvironment, poor self-repairing ability of AF cells and deficient matrix production. In this study, electrospinning technology is used to construct aligned core-shell nanofibrous scaffolds loaded with transforming growth factor-beta 3 (TGF beta 3) and ibuprofen (IBU), respectively. The results confirm that the rapid IBU release improves the inflammatory microenvironment, while sustained TGF beta 3 release enhances nascent extracellular matrix (ECM) formation. Biomaterials for clinical applications must repair local AF defects during herniectomy and enable AF regeneration during disc replacement, so a box defect model and total IVD replacement model in rat tail are constructed. The dual-drug delivering electrospun scaffolds are assembled into angle-ply structure to form a highly biomimetic AF that is implanted into the box defect or used to replace the disc. In two animal models, it is found that biomimetic scaffolds with good anti-inflammatory ability enhance ECM formation and maintain the mechanical properties of IVD. Findings from this study demonstrate that the multifunctional nanofibrous scaffolds provide inspirations for IVD repair.