A Bifunctional Biomaterial with Photothermal Effect for Tumor Therapy and Bone Regeneration

Malignant bone tumor is one of the major bone diseases. The treatment of such a bone disease typically requires the removal of bone tumor and regeneration of tumor-initiated bone defects simultaneously. To address this issue, it is required that implanted biomaterials should combine the bifunctions of both therapy and regeneration. In this work, a bifunctional graphene oxide (GO)-modified β-tricalcium phosphate (GO-TCP) composite scaffold combining a high photothermal effect with significantly improved bone-forming ability is prepared by 3D-printing and surface-modification strategies. The prepared GO-TCP scaffolds exhibit excellent photothermal effects under the irradiation of 808 nm near infrared laser (NIR) even at an ultralow power density of 0.36 W cm^-2, while no photothermal effects are observed for pure β-TCP scaffolds. The photothermal temperature of GO-TCP scaffolds can be effectively modulated in the range of 40-90 °C by controlling the used GO concentrations, surface-modification times, and power densities of NIR. The distinct photothermal effect of GO-TCP scaffolds induces more than 90% of cell death for osteosarcoma cells (MG-63) in vitro, and further effectively inhibits tumor growth in mice. Meanwhile, the prepared GO-TCP scaffolds possess the improved capability to stimulate the osteogenic differentiation of rabbit bone mesenchymal stem cells (rBMSCs) by upregulating bone-related gene expression, and significantly promote new bone formation in the bone defects of rabbits as compared to pure β-TCP scaffolds. These results successfully demonstrate that the prepared GO-TCP scaffolds have bifunctional properties of photothermal therapy and bone regeneration, which is believed to pave the way to design and fabricate novel implanting biomaterials in combination of therapy and regeneration functions. A facile strategy is applied by combining 3D printing and GO surface modification to prepare bifunctional GO-TCP scaffolds. The prepared GO-TCP scaffolds have bifunctional properties of photothermal therapy and bone regeneration, which is believed to pave the way to design and fabricate novel implanting biomaterials in combination of therapy and regeneration functions.