Effects of structure on the degradation behavior and osteogenic properties of 3D-printed Mg-Ti interpenetrating...

Magnesium-titanium (Mg-Ti) composites have the potential in applications to bone repair and orthopedic implants due to their mechanical properties derived from Ti and biological functions derived from Mg. However, the degradation rate of Mg in the composite is accelerated due to the effect of galvanic corrosion, which has affected its clinical application. In order to regulate the degradation behavior of Mg-Ti composites,3D printing technology was employed to prepare Ti scaffolds with porous structures of different pore areas and pore shapes (square, hexagonal, and triangular), then Mg was infiltrated into the porous Ti scaffold to obtain the Mg-Ti composites. The results showed that the groups with smaller pore areas had a faster initial degradation rate and could reach a stable stage earlier. The degradation of the square structure composite was more controllable compared to the other two composites, so it was selected for the subsequent study on osteogenic properties. The addition of Mg in the composite enhanced the apatite-forming ability, upregulated the expression of osteogenic-related genes such as RUNX2, ALP, and OPN, and promoted the generation of bone tissue and collage. The results indicated that the Mg-Ti composite could regulate the content and the degradation rate of Mg through structure, thereby improving the osteogenic properties by regulating the release of Mg²⁺ in the surrounding microenvironment. This study explored the degradation mechanism and systematically established a relationship between structure, degradation, and osteogenesis of Mg-Ti composites, thereby providing ideas for the structural optimization of Mg-Ti composites and offering references for applications in medical bone repair.