Injectable polymers being an advanced research has been studied now clinically in many applications. For example, Jiang et al. developed an injectable polymer-based material for irregular bone defects, using bone marrow stromal cells (BMSCs) encapsulated in mechanically reinforced hydrogel microspheres. Sodium alginate, being a biocompatible material, has low mechanical strength and cell viability to support bone regeneration. In this study, the microspheres were prepared from sodium alginate reinforced with xonotlite (Ca6Si6O17(OH)2, CSH) nanowires, which provide good mechanical strength and promote bone growth along with BMSCs. The in vitro and in vivo studies on femoral condyles of rats, gave a promising approach for bone regeneration in this method . Zhou et al. presented a promising new therapeutic strategy for intervertebral disc degeneration (IVDD) using immune-defensive microspheres.