"Antenna Effect"-Enhanced AuNPs@rGO Photothermal Coating Promotes 3D Printing of Osteogenic Active Scaffolds to Repair Bone Defects after Malignant Tumor Surgery

Malignant bone tumor defects are difficult to treat because of the simultaneous need for tumor treatment and bone-repair promotion. This study presents a bioactive composite scaffold (T-rGO@Au) for personalized bone defect repair and bone tumor treatment. The T-rGO@Au scaffold has a porous structure, and its mechanical properties are close to those of human cancellous bone. The T-rGO@Au scaffold can induce upregulation of osteopontin (OPN), RUNX-2, and osteocalcin (OCN) gene expression. In vivo experiments showed that the bone volume/total volume (BV/TV) ratio with the T-rGO@Au scaffold was the highest. The new bone was tightly integrated with the implant, demonstrating effective osseointegration. The T-rGO@Au scaffold locally generated high temperatures and reactive oxygen species under near-infrared excitation, and AuNPs enhanced the photothermal performance of rGO through the "antenna effect." Furthermore, in vitro experiments showed that the tumor cell nuclei were destroyed, late-stage apoptotic cells increased, and cell morphology was severely damaged. Additionally, RNA-seq revealed that tumor cell destruction was mediated through signaling pathways, such as the MAPK pathway. In vivo antitumor experiments also demonstrated that the T-rGO@Au scaffold significantly inhibited the growth of tumor cells within 2 weeks. Thus, the T-rGO@Au scaffold provides a new treatment strategy for the development of implantable scaffolds for bone tumor defects.