Research Progress of Functional Polymer for Spinal Cord Regeneration

Spinal cord injury (SCI) is a severe and irreversible injury in the central nervous system, which often leads to permanent motor and sensory dysfunction. The outcome of nerve regeneration after SCI is mostly limited by the resulting adverse microenvironment from the spontaneous inflammatory cells infiltration and host cell death. The activation and accumulation of macrophages/microglia at the lesion sites often leads to secondary damage, including neuron death, astrocyte gliosis and collagen fibrosis, which eventually impairs biological functions of neural stem cells, such as migration and differentiation, either endogenously or exogenously. Although recent studies have shown that axons can regenerate in a suitable matrix environment after spinal cord injury, there is no feasible measure for functional recovery. In recent years, biomaterial scaffold-based strategies have become an attractive alternative for neural regeneration. Biocompatible polymers have multiple functions: promoting cell growth and differentiation; minimizing cavitation, inhibiting cicatrization and astrocytes/collagen accumulation; presenting nonspecific infiltration of inflammatory cells; serving as carriers of cells and bioactive factors. Therefore, polymer scaffolds have been investigated as potential therapies for SCI. This review will highlight the compositions, forms and microenvironment construction of polymer scaffolds for SCI treatment. Additionally, the peculiar properties of the polymer materials used in the therapeutic process of SCI also show new guiding significance for tissue engineering approaches.