Intervertebral disc design and development in three-dimensional bioprint environment

The intervertebral disc (IVD) provides flexibility and load-bearing capacity of the spine. IVD degeneration disrupts the biomechanics of the spine, causing pain and loss of function.Personalized biocompatible discs provide treatment according to patient needs. The aim of the presented study is to develop personalized, three-dimensional (3D) biocompatible disc constructs using computer modeling of L5-S1 vertebral disc based on real cadaveric data and cartilage extracellular matrix (ECM). In addition, to optimize the bioink composition of these constructs with experimental design and to produce them using 3D bioprinting technology. In the first phase of the study, a 3D IVD scaffold was designed using cadaver data using computer aided design (CAD). The L5-S1 disc was custom-created according to the cambin triangle and the design was presented in stereolithography (*STL) format. In the second stage, IVD integration was performed with computer-aided manufacturing (CAM) and bioink composition was determined with full factorial design. With the most ideal combination, high precision and efficiency were achieved in personalized 3D bioprinting. In the final stage, the effectiveness of the personalized L5-S1 vertebral disc produced by 3D bioprinting method with the experimental bioink composition, using dityrosine and zein crosslinkers, was evaluated by rheological analysis and biocompatibility tests. Determining the optimum bioink composition of personalized tissue scaffolds formed with 3D bioprinting with the experimental design minimized the time and cost in mimicking the natural microenvironment. In addition, it allows pre-operative planning. Therefore, the presented work has a very high impact for biotechnological aspect.