Bone-like hydroxyapatite anchored on alginate microspheres for bone regeneration

Inspired by the initial mineralization process in bone matrix vesicles (MVs), we used Dulbecco's Modified Eagle's Medium (DMEM) to establish the similar physiological environment to that in MVs for biomimetic mineralization on alginate (ALG) microspheres. The results showed that HA crystals were firstly formed and anchored on the membrane of microspheres like the initial deposition of hydroxyapatite crystals inside MVs. With the continuous growth and accumulation of mineral crystals, HA coating was finally formed on ALG microspheres. The mineralized ALG microspheres (M-ALG microspheres) show good biocompatibility and osteogenic performance. The HA coating is also conducive to the active migration of osteoblasts to the surface of M-ALG microspheres. Collectively, bone-like HA crystals anchored on ALG microspheres may provide a good prospect to promote the repair of bone defects.