Study of the Cytotoxic Effect of Au@Rh Core-Shell Metal Particles on the Osteosarcoma Cell Line HOS and the hFOB Osteoblast Cell Line

Osteosarcoma, the most common primary malignant bone tumor in adolescents, faces treatment challenges due to metastasis and chemoresistance. This study developed a novel Au@Rh core-shell nanoparticle system functionalized with indocyanine green (ICG) to overcome hypoxia-limited photodynamic therapy (PDT). Au@Rh nanoparticles were synthesized via wet chemistry, characterized by UV-Vis spectroscopy, TEM, and cyclic voltammetry (CV). The system exhibited core-shell morphology, defined crystalline planes, photothermal conversion and electrocatalytic activity. The Au@Rh nanoparticles (109 nm total size, 90 nm Au core, 15 nm Rh shell) demonstrated dual functionality: the gold core provided photothermal conversion (7 °C temperature increase under NIR irradiation), while the rhodium shell exhibited pH-independent electrocatalytic activity for H₂O₂ decomposition, generating oxygen to alleviate tumor hypoxia. Crucially, the system showed excellent biocompatibility, with no significant cytotoxicity in both osteosarcoma (HOS) and normal osteoblast (hFOB) cells after 48-hour exposure. When activated by NIR irradiation (808 nm, 16.6 J/cm²), the complete Au@Rh-ICG system achieved selective 67% cytotoxicity in HOS cells versus only 30% in hFOB cells, demonstrating targeted therapeutic efficacy. These results position Au@Rh-ICG as a promising theranostic platform for osteosarcoma treatment, combining enhanced PDT with photothermal therapy while addressing tumor hypoxia.