Increased radiotoxicity in two cancerous cell lines irradiated by low and high energy photons in the presence of thio-glucose bound gold nanoparticles.

PURPOSE: Gold nanoparticles modified by thio-glucose are believed to increase the toxicity of radiotherapy in human malignant cells. We report the effect of thio-glucose bound gold nanoparticles (Glu-G nanoparticles), 16 nm in size, on two human lung (QU-DB) and breast (MCF7) cancer cell lines combined with kilo and megavoltage X-rays. MATERIALS AND METHODS: The shape and surface characteristics, the size distribution and light absorption spectrum of the prepared nanoparticles were measured by transmission electron microscopy, dynamic light scattering, and ultraviolet-visible spectrophotometry, respectively. The cell uptake was assayed using the atomic absorption spectrometry. Mitochondrial activity, colony formation, and comet assays were applied to assess and compare the enhanced radiotoxicity of 100 KV and 6 MV X-rays, when combined with Glu-G nanoparticles. RESULTS: Glu-G nanoparticles had no significant toxicity for MCF7 and QU-DB cells up to 100 micromolar concentration. Compared to radiation alone, the intracellular uptake of Glu-G nanoparticles resulted in increased inhibition of cell proliferation by 64.1% and 38.7% for MCF7 cells, and 64.4% and 32.4% for QU-DB cells by 100 kVp and 6 MV X-rays, respectively. Comet assay confirmed an increase of DNA damage as a result of combination of 6 MV photons with Glu-G nanoparticles. CONCLUSION: Glu-G nanoparticles have remarkable potential for enhancing radiotoxicity of both low and high energy photons in MCF7 and QU-DB cells.