Surface-modified 3D-printed sphene scaffolds for photothermal osteosarcoma therapy and osteogenic stimulation

Bone cancer treatment following surgical resection requires the elimination of residual tumor cells while promoting the regeneration of tumor-associated bone defects. Here, we developed a hierarchically surface-engineered, 3D-printed sphene scaffold (SPH, CaTiSiO₅) integrating photothermal tumor ablation with osteogenic-supportive properties. Scaffolds fabricated from sol-gel-derived SPH powder were sequentially modified with an ordered mesoporous bioactive glass (OMBG) coating and a black phosphorus-polydopamine (BP-PD) nanocomposite. OMBG promoted calcium phosphate-rich mineral deposition and osteogenic differentiation and also displayed NIR-induced heating, while the subsequent BP-PD deposition further increased the photothermal response and tumor-cell ablation. In vitro, the modified scaffolds showed favorable cytocompatibility, enhanced osteogenic differentiation of human mesenchymal stem cells, and efficient photothermal killing of K7M2 osteosarcoma cells. In a rabbit distal femoral VX2 malignant bone tumor model, the scaffold significantly suppressed local tumor growth and invasion, reduced systemic tumor-associated deterioration and distant organ metastasis, and improved therapeutic outcomes without detectable systemic cytotoxicity. 3D MRI-CT fusion reconstruction confirmed reductions in solid tumor volume, peritumoral edema, and intramedullary invasion, demonstrating effective local tumor control and preservation of peri-implant bone within a single implantable therapeutic system. These findings establish surface-engineered SPH scaffolds as a multifunctional platform that combines effective local tumor control and preservation of peri-implant bone in vivo with osteogenic-supportive activity demonstrated in vitro.