A Novel Injectable Composite Hydrogel HAp‐GelMA Co‐Doped Magnesium/Zinc Promotes Bone Generation and Angiogenesis Synergistically

Bone is a crucial organ in the human body; however, conventional bone repair materials, such as autologous and allogeneic bone, are associated with challenges like limited availability and infection risks. Therefore, the development of novel biomaterials for bone repair is essential. This study employed a hydrothermal method to synthesize hydroxyapatite (HAp) doped with various elements and characterized its physicochemical properties. These findings show that the doped HAp particles have a uniform spherical shape and an even distribution of elements. Subsequently, HAp-GelMA composite hydrogels are synthesized, and their mechanical properties and injectability are assessed. The addition of HAp significantly enhanced the stability of the composite hydrogel, making it suitable for the rapid filling of bone defects. In vitro experiments demonstrated that the Zn/Mg dual-doped composite hydrogel effectively promoted cell proliferation and angiogenesis. Furthermore, In vivo studies using a cranial defect model in rats show that the Zn/Mg dual-doped group exhibited significantly better bone regeneration compared to the control group, indicating the material's potential application value in bone tissue engineering and regenerative medicine. In summary, the composite hydrogel scaffold developed in this study shows promising prospects for enhancing angiogenesis and osteogenesis.