biostudies-literatureUnknown21Hayashi KSynthetic bone grafts are in high demand owing to increased age-related bone disorders in the global aging population. Here, we report fabrication of gear-shaped granules (G-GRNs) for rapid bone healing. G-GRNs possessed six protrusions and a hexagonal macropore in the granular center. These were composed of carbonate apatite, i.e., bone mineral, microspheres with ∼1-μm micropores in the spaces between the microspheres. G-GRNs formed new bone and blood vessels (both on the granular surface and within the macropores) 4 weeks after implantation in the rabbit femur defects. The formed bone structure was similar to that of cancellous bone. The bone percentage in the defect recovered to that in a normal rabbit femur at week-4 post-implantation, and the bone percentage remained constant for the Computational and structural biotechnology journal2514-2523https://www.ebi.ac.uk/biostudies/studies/S-EPMC10106487biostudies-literatureGear-shaped carbonate apatite granules with a hexagonal macropore for rapid bone regeneration.PMC10106487Hayashi KYanagisawa TKishida RTsuchiya AIshikawa KfalseGear-shaped carbonate apatite granules with a hexagonal macropore for rapid bone regeneration.Synthetic bone grafts are in high demand owing to increased age-related bone disorders in the global aging population. Here, we report fabrication of gear-shaped granules (G-GRNs) for rapid bone healing. G-GRNs possessed six protrusions and a hexagonal macropore in the granular center. These were composed of carbonate apatite, i.e., bone mineral, microspheres with ∼1-μm micropores in the spaces between the microspheres. G-GRNs formed new bone and blood vessels (both on the granular surface and within the macropores) 4 weeks after implantation in the rabbit femur defects. The formed bone structure was similar to that of cancellous bone. The bone percentage in the defect recovered to that in a normal rabbit femur at week-4 post-implantation, and the bone percentage remained constant for the 2023-01-01T00:00:00Z20232025-04-18T14:52:38.492Z2025-04-07T01:12:03.052ZS-EPMC101064873707717510.1016/j.csbj.2023.03.053