Enhancing the effect of 4 MeV electron beam using gold nanoparticles in breast cancer cells

Gold nanoparticles (GNPs) have been applied as radiosensitizer in radiotherapy. Limited reports have shown that GNPs may be effective as a dose enhancer agent for electron radiation therapy. Some Monte Carlo Simulation studies have shown that selecting suitable size of GNPs and electron energies are critical for effective dose enhancement. The aim of this study was to assess possible radiosensitization effect of GNPs on cancer cell treated with 4 MeV electron beams. Approximately 10 nm GNPs were synthesized and characterized by electron microscope and dynamic light scattering. MCF-7 and MDA-MB231 breast cancer cells were used and their viability was measured by MTT assay. Radiosensitization effect of GNPs under 4 MeV electron beams was measured by clonogenic assay. The result showed a concentration dependent uptake of GNPs without reducing cell viability at concentrations <= 50 mg/L. Incubation of cancer cells with GNPs caused a significant decrease in their viability following exposure to electron beams as well as a decrease in their survival fraction when compared to control. The sensitizer enhancement ratio (SER) by electron beams in MCF-7 cells was 1.43 and 1.40 in presence of 25 and 50 mg/L GNPs, respectively. For MDA-MB-231 cells, it was 1.62 in presence of 25 mg/L GNPs. Our data demonstrated the significant dose enhancement of the GNPs in combination with 4 MeV electron beams that could be applicable for the treatment of superficial tumors and intra operative radiation therapy. (C) 2017 Published by Elsevier Ltd on behalf of Associazione Italiana di Fisica Medica.