Bio-based Hydrogels and Their Application for Intervertebral Disc Regeneration

The intervertebral disc is a complex hierarchical structure, functiondependent, with the main function to provide support during movements, thus functioning as the shock absorber of the vertebral column. Its properties change from the outer toward the inner part, following the diverse composition. It is avascular with poor self-healing capability. During the degeneration process, the cascade of events causes the rupture of the structure and of the extracellular matrix, not able anymore to sustain load stress, leading to cervical or low back chronic pain. Current clinical treatments aim at pain relief but according to the severity of the disease, it might require spinal fusion or a total disc replacement made of metal or plastic disc substitutes, thus reducing the patient’s mobility. Tissue engineering and naturally derived hydrogels are gaining interest as important tools for mimicking and delivering cells or molecules either to regenerate a damaged part of the disc, but also its whole structure. Although in the last due decades several improvements have been achieved , the fabrication of IVD constructs, reproducing its structure and functions, is still challenging. For example the standardization of cell cultures conditions,cell sources, mechanical tests paramters, are fundamental achievements to translate the biofabricated products to the clinic.