3D-printed gallium-doped calcium silicate bioceramic scaffolds with high strength and osteogenesis-promoting properties

As the incidence of bone injuries continues to rise, calcium silicate (CSi) ceramics have attracted significant attention as a prominent area of research for the creation of artificial bone implants for mending bone defects. However, their low mechanical strength and rapid degradation rate pose significant challenges to bone repair, especially for the thin-walled bone defects with specific mechanical requirements, limiting their application in bone repair. This study modifies the CSi ceramics by doping them with the gallium ions and develops the gallium-doped calcium silicate (CSi-Gax) scaffolds with good mechanical strength and degradation performance based on projection-based 3D printing technology. The effects of gallium ion doping amount (x mol%), sintering temperature, and pore size on the scaffold strength were systematically investigated. At a temperature of 1100 °C, the CSi-Gax scaffolds demonstrated notable mechanical performance, with the compressive strength of the CSi-Ga3 scaffold being nearly double that of the pure CSi scaffold, reaching approximately 52 MPa. In vitro degradation studies revealed that the CSi-Ga3 scaffold retained substantial compressive strength (exceeding 27 MPa) and an elastic modulus (greater than 294 MPa) after being immersed in Tris buffer solution for three weeks. Additionally, it demonstrated commendable bioactivity and osteogenic performance. The findings suggest that the CSi-Ga3 scaffold exhibits outstanding mechanical and biological properties, rendering it highly suitable for in situ bone repair.