Advances in Hydrogel Tissue Engineering for Spinal Cord Injury Repair

Spinal cord injury (SCI), which is a severe complication of spinal fractures, often causes the dysfunction of the spinal cord and results in sensory and motor abnormalities. Current clinical treatments-including medication, decompression surgery, and bed rest-remain insufficient for complete functional recovery. It is necessary to reduce the early inflammatory reactions, rebuild the connections of neurons, and reduce the formation of the glial scar in order to restore spinal cord function. With the development of biomaterials discipline, hydrogel tissue engineering has become an effective and feasible method. Injectable and highly biocompatible hydrogel can directly fill the injured site as a scaffold material that can provide physical support to reduce scar formation and promote axon growth. In addition, hydrogels have the ability to regulate pathophysiological events. For example, it can reduce inflammatory reactions, inhibit glial scar formation, and promote axonal growth, so as to achieve the recovery of motor function after SCI. This review systematically correlates the four pathological phases of SCI with the stage-specific biological functions of hydrogels. It summarizes the current state of research in SCI and hydrogel-based tissue engineering, and discusses the key challenges and future directions in this evolving field.