Tóm tắt

Nanostructured hydroxyapatite (HAp) has been applied widely as a scaffold material f or bone tissue en gineering for its good osteoinduction and biodegradability. However, the degradation process and the distribution of degraded HAp within the bone-defect cavity is still not clear. To visually study the behav ior of HAp in bone repair process, a membrane of HAp/terbium (Tb)-HAp nanowires (NWs) was prepared with a concentric circle structure (CCS), of which the inner circle and the outer ring were constructed with Tb-HAp and HAp NWs, respectively. HAp/Tb-HAp CCS membrane possessed good osteogenic capac ity and efficient fluorescence in the center for visualization. The in vitro experimental results proved that the Tb-HAp and HAp NWs membranes both presented high cytocompatibility and adequate efficiency to induce osteogenic differentiation of bone marrow stem cells (BMSCs). HAp/Tb-HAp CCS membranes were then implanted into a rat calvarial bone-defect model to study the behavior of HAp in bone repair process in vivo by tracking the fluorescence distribution. The results showed that the fluorescence of Tb-HAp dif fused gradually from the inner circle to the outer ring, which suggested that the HAp was first degraded, and then the degraded product was diffused and finally reconstructed. Further, the histological results proved that the doping of Tb did not impair the promotive effect of HAp on bone repair process. There fore, this study provided a visual method to observe the degradation-diffusion-reconstruction behavior of HAp nanomaterials in bone repair process.