A Biomimetic Silk Fibroin/Chitosan Membrane for Annulus Fibrosus Sealing to Prevent Intervertebral Disc Re-Herniation

Intervertebral disc (IVD) herniation causes low back pain and even disability. Microdiscectomy surgery, a common treatment for IVD herniation, often leads to re-herniation, necessitating effective methods to seal the annulus fibrosus (AF) defect during surgery. However, developing a suitable AF sealing implant remains a grand challenge, due to the superior performance of natural AF. Herein, a biomimetic silk fibroin/chitosan membrane (BSC) is designed to seal the defect AF and prevent IVD re-herniation. The BSC with a layered orientation structure exhibits an AF biomimetic structure, and high mechanical properties (tensile modulus of 28 MPa, tensile strain of 357%), which match the mechanical properties of natural AF (tensile modulus of 11-29 MPa, and tensile strain of greater than 65%), and tissue adhesion with adhesion performance to pig skin of 59 kPa and to bovine AF of 42 kPa. In a model of a box defect on rat caudal AF, the BSC effectively seals the AF defect, maintains the structural integrity of the defective IVD, and mitigates its degenerative process. This BSC shows promising potential for the prevention of IVD re-herniation.