Multifunctional design of 3D-printed TPMS-structured ZrO₂/CSi-Mg/Ga composite scaffolds for enhanced mechanical, antibacterial, and osteogenic performance

In clinical practice, the repair of alveolar bone defects remains a major challenge, primarily due to the demanding requirements for scaffold mechanical properties, antibacterial activity, and bioactivity. In this study, we fabricated a zirconia (ZrO₂) scaffold matrix via projection-based 3D printing technique and subsequently integrated it with bioactive coatings of magnesium-doped calcium silicate (CSi-Mg) and nano-liquid gallium (nano-Ga) to construct a novel composite scaffold for enhanced bone regeneration. Among the different architectures, the triply periodic minimal surface (TPMS) structure exhibited the best mechanical performance, reaching a maximum compressive strength of up to 1200 MPa. After modification with the CSi-Mg coating, the compressive strength increases to over 1230 MPa. Notably, the scaffolds maintained a compressive strength exceeding 1200 MPa after three weeks of degradation in Tris-buffer solution. The ZrO₂/CSi-Mg/Ga composite achieved an inhibition rate of over 50% against pathogenic bacteria. Moreover, the scaffold effectively supported cell viability and promoted the osteogenic differentiation of bone marrow mesenchymal stem cells. Collectively, this ZrO₂/CSi-Mg/Ga composite scaffold, featuring a TPMS architecture and a multifunctional coating, offers an exceptional combination of high mechanical robustness, significant antibacterial efficacy, and favourable bioactivity, positioning it as a highly promising candidate for applications in oral and maxillofacial bone regeneration.