Injectable hydrogels for spinal cord injury repair

Spinal cord injury (SCI) often causes severe functional impairment of body, which leads to a huge burden to the patient and the whole society. Many strategies, especially biomaterials, have been employed for SCI repair. Among various biomaterials, injectable hydrogels have attracted much attention because of their ability to load functional components and be injected into the lesioned area without surgeries. In this review, we summarize the recent progress in injectable hydrogels for SCI repair. We firstly introduce the pathophysiology of SCI, which reveals the mechanism of clinical manifestations and determines the therapeutic schedule. Then, we describe the original sources of polymers and the crosslinking manners in forming hydrogels. After that, we focus on the in vivo therapeutic strategies and effects of injectable hydrogels. Finally, the recent challenges and future outlook of injectable hydrogel for SCI repair are concluded and discussed. We believe this review can be helpful and inspire the further development of injectable hydrogels for SCI repair.