▎ 摘　　要

The custom-tailored medicine requires a developmental strategy that integrates excellent osteogene-sis with mechanical stability to enhance the reconstruction of the critical-size bone defect (CSBD) and the healing process in weight-bearing bone. We prepared three-dimensional (3D) printed biphasic cal-cium phosphate (BCP) scaffolds composited with nano-graphene oxide (GO). The biological effects of the GO/BCP composite scaffolds could induce the differentiation of rat bone marrow stem cells (BM-SCs) and the migration of human umbilical vein endothelial cells (HUVECs) for bone repair. The proper ratio of GO in the composite scaffold regulated the composites' surface roughness and hydrophilicity to a suitable range for the adhesion and proliferation of BMSCs and HUVECs. Besides, the GO/BCP composite scaffold increased osteogenesis and angiogenesis by activating BMP-2, RUNX-2, Smad1/4, and VEGF. The customized intramedullary nail combined with GO/BCP scaffold was applied to repair CSBD (2.0 cm in length) in a beagle femur model. This fixation strategy was confirmed by finite element analysis. In vivo, the results indicated that the custom-made internal fixation provided sufficient stability in the early stage, ensuring bone healing in a considerable mechanical environment. At 9 months postoperatively, longitudi-nal bony union and blood vessels in osteon were observed in the CSBD area with partial degradation in the 0.3% GO/BCP group. In the three-point bending test, the ultimate load of 0.3% GO/BCP group reached over 50% of the normal femur at 9 months after repair. These results showed a promising application of osteogenic GO/BCP scaffold and custom-made intramedullary nails in repairing CSBD of the beagle femur. This effective strategy could provide an option to treat the clinical CSBD in weight-bearing bones.(c) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.