Porous Ti3SiC2 ceramics with improved osteogenic functions via biomineralization as load-bearing bone implants

Ti3SiC2 ceramics exhibit excellent mechanical properties and good biocompatibility, rendering them promising bone substitutes for load-bearing conditions. However, the bone integration and osteogenic ability of Ti3SiC2 ceramics remain unclear. Herein, porous Ti3SiC2 ceramics were prepared and systematically investigated as bone scaffolds. The Ti3SiC2 scaffolds with a porosity of 62.9% ± 2.5% showed high compressive strength ∼68.12 ± 4.33 MPa. Silicon hydroxyl groups formed on the surface of Ti3SiC2 after soaking in simulated body fluid, which played a critical role in the apatite mineralization of the scaffolds. Biomineralization of Ti3SiC2 scaffolds was found when implanted subcutaneously in the rat dorsum for 2 weeks, demonstrating good osteogenesis ability. The apatite mineralization of the Ti3SiC2 scaffold facilitated the polarization of RAW264.7 cells from M1 to M2 phenotype, which also promoted the differentiation of MC3T3-E1 cells. The porous Ti3SiC2 scaffolds improved osteointegration and bone regeneration after implantation in rabbit femoral defects. Impressively, the number of the newly formed trabeculae in the Ti3SiC2 group was three times of the control group after implantation for 8 weeks, showing excellent bone defect repair. This work demonstrates that Ti3SiC2 implants with improved biological functions likely via in-situ biomineralization are promising candidates for bone regeneration.