Engineered Cell-Laden Armor Unit-Mimicking Bioceramic Granules for Bone Regeneration

Bioceramic granules have been used as fillers for the repair of various bone defects, but structural instability leads to susceptibility to displacement or dislodgement in practice. Armor unit is a concrete block placed along the breakwater to resist waves and protect the dike. Inspired by this, an armor unit-mimicking (AU) bioceramic granule by three-dimentional (3D) printing is developed, and combine it with adipose-derived stem cells (ADSCs) overexpressing fibroblast growth factor 23 (FGF23) to construct tissue-engineered bone. In vitro results show that AU granules and FGF23 transfection synergistically promote osteogenic differentiation of ADSCs. For the repair of beagle femoral metaphyseal defects, the implanted AU granules are stacked and interlocked to form an impact-resistant porous scaffold. With the assistance of ADSCsFGF23, AU granules exhibit enhanced new bone formation and host bone maintenance. Taken together, these findings demonstrate the potential of 3D-printed AU granules in combination with FGF23-overexpressing ADSCs as a novel bone void filler for ease of handling and enhanced bone regeneration. Inspired by the armor units stacked along the breakwater, an armor unit-mimicking (AU) bioceramic granule is proposed as a novel bone void filler. For the repair of critical-size beagle femoral metaphyseal defects, AU granules show ease of handling from structural stability and enhanced bone regeneration with the assistance of adipose-derived stem cells overexpressing fibroblast growth factor 23.image