A novel phosphorylated chitin-hydroxyapatite composite promotes angiogenesis and osteogenesis for bone defect repair.

Current bone repair materials face limitations including donor site morbidity, immune rejection, and insufficient osteogenic capacity. To overcome these challenges, tissue engineering has introduced bioactive composites that better mimic the natural bone microenvironment. Here, we developed a novel composite by integrating phosphorylated chitin, which is an excellent biocompatible and bioactive organic polymer, with biogenic hydroxyapatite, a mineral phase closely resembling native bone. The composite was systematically characterized for its physicochemical properties. In vitro studies demonstrated the angiogenic and osteogenic activities of phosphorylated chitin, which were further enhanced by the introduction of magnesium ions. In vivo experiments using rat calvarial defect and rabbit alveolar defect models confirmed its superior bone regeneration capability, with effective promotion of new bone formation. These results underscore the outstanding osteogenic potential of this composite, offering a promising strategy for effective bone defect repair.