Tissue engineering provides a path forward for emerging personalized medicine therapies as well as the ability to bring about cures for diseases or chronic injuries. Traumatic spinal cord injuries (SCIs) are an example of a chronic injury in which no cure or complete functional recovery treatment has been developed. In part, this has been due to the complex and interconnected nature of the central nervous system (CNS), the cellular makeup, its extracellular matrix (ECM), and the injury site pathophysiology. One way to combat the complex nature of an SCI has been to create functional tissue-engineered scaffolds that replace or replenish the aspects of the CNS and tissue/ECM that are damaged following the immediate injury and subsequent immune response. This can be achieved by employing the tissue-engineering triad consisting of cells, biomaterial(s), and environmental factors. Stem cells, with their innate ability to proliferate and differentiate, are a common choice for cellular therapies. Natural or synthetic biomaterials that have tunable characteristics are normally used as the scaffold base. Environmental factors can range from drugs to growth factors (GFs) or proteins, depending on if the idea would be to stimulate exogeneous or endogenous cell populations or just simply retain cells on the scaffold for effective transplantation. For functional regeneration and integration for SCI, the scaffold must promote neuroprotection and neuroplasticity. Tissue-engineering strategies have shown benefits including neuronal differentiation, axonal regeneration, axonal outgrowth, integration into the native spinal cord, and partial functional recovery. Overall, this review focuses on the background that causes SCI to be so difficult to treat, the individual components of the tissue-engineering triad, and how combinatorial scaffolds can be beneficial toward the prospects of future SCI recovery.
Keywords: biomaterials; environmental factors; spinal cord injury; stem cells; tissue engineering.