Fabrication and Evaluation of a Novel Integrated Annulus Fibrosus-Nucleus Pulposus Hybrid Scaffold

The scope of this study was to fabricate and evaluate a novel integrated annulus fibrosus-nucleus pulposus scaffold composed of bone matrix gelatin (BMG) and cartilage extracellular matrix (ECM) respectively. Scaffolds were fabricated by a serial physicochemical and free-drying process. The physiochemical property and compatibility of the composite scaffold with intervertebral disc cells were evaluated. HE staining showed no residual cells in both annulus fibrosus and nucleus pulposus scaffolds. SEM observation revealed that the integration of annulus fibrosus region and nucleus pulposus region was well. The pore diameter of annulus fibrosus scaffold is about 401.4±13.1 μm and the nucleus pulposus scaffold 112.4±21.8 μm, which demonstrated that the composite scaffolds possess interconnected pores structure. The average compressive elastic modulus of the integrated scaffold was 49.06 ±15.57 kpa, which was lower than that of porcine coccyx intervertebral disc, 135.9±28.9 kPa. SEM observation and LIVE/DEAD staining showed good adhesion and high viability of intervertebral disc cells in the integrated scaffold. In conclusion, the integrated annulus fibrosus-nucleus pulposus scaffold can be used for intervertebral disc tissue engineering because of its non-immunogenicity, preservation of ECM composition, good physicochemical property and high biocompatibility with interbertebral disc cells.