Multimodal cancer cell therapy using Au@Fe₂O₃ core-shell nanoparticles in combination with photo-thermo-radiotherapy

In this study, gold coated iron oxide nanoparticle (Au@Fe₂O₃ NP) was synthesized in a core-shell structure. Photothermal and radiosensitization effects of Au@Fe₂O₃ NPs were investigated on KB human mouth epidermal carcinoma cell line. Cell death and apoptosis were measured to study the effects of nanoparticles in combination with both radiotherapy (RT) and photothermal therapy (PTT). The KB cells were treated with Au@Fe₂O₃ NPs (20 μg/ml; 4 h) and then received different treatment regimens of PTT and/or RT using laser (808 nm, 6 W/cm², 10 min) and/or 6 MV X-ray (single dose of 2 Gy). Following the various treatments, MTT assay was performed to evaluate the cell survival rate. Also, the mode of cell death was determined by flow cytometry using an annexinV-fluorescein isothiocyanate/propidium iodide apoptosis detection kit. No significant cell death was observed due to laser irradiation. The viability of the cells firstly incubated with NPs and then exposed to the laser was significantly decreased. Additionally, our results demonstrated that Au@Fe₂O₃ NP is a good radiosensitizer at megavoltage energies of X-ray. When nanoparticles loaded KB cells were received both laser and X-ray, the cell viability substantially decreased. Following such a combinatorial treatment, flow cytometry determined that the majority of cell death relates to apoptosis. In conclusion, Au@Fe₂O₃ NP has a great potential to be applied as a photo-thermo-radiotherapy sensitizer for treatment of head and neck tumors.