Injectable and assembled 3D solid structure for free-to-fixed shape in bone reconstruction

There is a gap between injectable and scaffold-like bioceramics. Injectable bioactive materials, such as bone cement and hydrogel, are good for minimized surgery, but the extremely low porosity and small pore size limited enhanced bone repair and regeneration. Macroporous bioceramic scaffolds are used because of the controlled pore size and porosity, but not injectable. It's a challenge of preparation of an injectable macroporous ceramic scaffold for minimized bone reconstruction. By using the reversible setting reaction of calcium sulfate and combining a dual setting system with magnesium silicate hydrate, the injectable and assembled 3D porous bioceramic scaffold has been successfully developed. The content of amorphous magnesium silicate hydrate in the dual setting system affected the mechanical strength and degradation. The porous structure could be controlled by the size of granules. The granules can also be used for the fabrication of porous materials with varied shapes and customized structures by using a simple injection process. The biological testing showed good biocompatibility and in vitro osteogenesis. By using the femoral lateral condyle defect model, we can see the granules could be injected into the defect and formed a rigid porous structure in situ, and further presented better new bone formation compared with autologous bone chips. Briefly, we demonstrated the first injectable 3D solid porous ceramic structure for minimized bone repair and free-form shaping.