Clickable Granular Hydrogel Scaffolds for Delivery of Neural Progenitor Cells to Sites of Spinal Cord Injury

Abstract Spinal cord injury (SCI) is a serious condition with limited treatment options. Neural progenitor cell (NPC) transplantation is a promising treatment option, and the identification of novel biomaterial scaffolds that support NPC engraftment and therapeutic activity is a top research priority. The objective of this study was to evaluate in situ assembled poly (ethylene glycol) (PEG)‐based granular hydrogels for NPC delivery in a murine model of SCI. Microgel precursors were synthesized by using thiol‐norbornene click chemistry to react four‐armed PEG‐amide‐norbornene with enzymatically degradable and cell adhesive peptides. Unreacted norbornene groups were utilized for in situ assembly into scaffolds using a PEG‐di‐tetrazine linker. The granular hydrogel scaffolds exhibited good biocompatibility and did not adversely affect the inflammatory response after SCI. Moreover, when used to deliver NPCs, the granular hydrogel scaffolds supported NPC engraftment, did not adversely affect the immune response to the NPC grafts, and successfully supported graft differentiation toward neuronal or astrocytic lineages as well as axonal extension into the host tissue. Collectively, these data establish PEG‐based granular hydrogel scaffolds as a suitable biomaterial platform for NPC delivery and justify further testing, particularly in the context of more severe SCI. This article is protected by copyright. All rights reserved