The design criteria and therapeutic strategy of functional scaffold for spinal cord injury repair

Spinal cord injury (SCI) remains a therapeutic challenge in clinic. Current drug and cell therapeutics have obtained significant efficacy but are still in the early stages for complete neural and functional recovery. In the past decades, functional scaffold (FS) has been rapidly developed to bridge the lesion and provide a framework for tissue regeneration in SCI repair. Moreover, FS can act as an adjuvant for locally delivering drugs in the lesion with a designed drug release profile, and supplying a biomimetic environment for implanted cells. In this review, the design criteria of FS for SCI treatment are summarized according to their biocompatibility, mechanical properties, morphology, architecture, and biodegradability. Subsequently, FSs designed for SCI repair in the scope of drug delivery, cell implantation and combination therapy are introduced, respectively. And how FS promotes their therapeutic efficacy is analyzed. Finally, the challenges, perspectives, and potential of FS for SCI treatment are discussed. Hopefully, this review may inspire the future development of potent FS to facilitate SCI repair in clinic.