Structural Interface Engineering Unlocks Native-Like Mechanics in Biomimetic Intervertebral Discs

The exceptional biomechanical performance of the intervertebral disc (IVD) arises from its complex hierarchical structure, where interlamellar and radial fiber networks play critical roles in load transfer and mechanical resilience. However, the precise contribution of these fiber networks remains incompletely understood. Here, we present a biomimetic strategy that replicates these native interfacial architectures using silk-based suture reinforcement, forming annulus fibrosus–nucleus pulposus (AF–NP) constructs designed to emulate native IVD functionality. Mechanical testing revealed that suture-reinforced laminates achieved superior shear resistance (0.87 ± 0.06 MPa) while reducing modulus variability from 43% to 4%, indicating enhanced interlamellar cohesion. Radial fibers further improved compressive performance, limiting radial expansion and maintaining internal pressurization under load. Finite element modeling demonstrated that radial fibers redistributed interfacial stresses, reduced peak stress concentrations, and enhanced circumferential fiber activation, promoting more uniform load distribution. These findings establish that interlamellar and radial fibers are essential for maintaining IVD structural integrity and optimizing load distribution. Our biomimetic design offers a robust framework for developing next-generation IVD repair and replacement constructs, providing insights that may advance clinical strategies for IVD degeneration and improve the durability of soft tissue implants.