Hydrogel and Microgel Collaboration for Spatiotemporal Delivery of Biofactors to Awaken Nucleus Pulposus‐Derived Stem Cells for Endogenous Repair of Disc

Depletion of nucleus pulposus-derived stem cells (NPSCs) is a major contributing factor to the attenuation of endogenous regenerative capacity in intervertebral disc degeneration (IVDD). Introducing a hydrogel drug delivery system is a potential strategy for counteracting endogenous cell depletion. The present study proposes a delivery platform for the spatiotemporal release of multiple drugs by combining sodium alginate hydrogels with gelatin microgels (SCGP hydrogels). The SCGP hydrogels facilitated the initial release of chondroitin sulfate (ChS) and the gradual release of an independently developed parathyroid hormone-related peptide (P2). The combined action of these two small molecule drugs "awakened" the reserve NPSCs, mitigated cell damage induced by H