Sensitization of Malignant Breast Epithelial cells to Proton Radiation by Metallic Nano-Particles

Abstract

Enhancing cancer treatment has garnered interest for more than 50 years. Enhancement has been considered in the evolution of treatment modalities as well as in the potential additives at the cellular level as radio-sensitizers. These enhancements all encompass the same goal: a method to spare healthy surrounding tissue while killing the cancerous tissue. In this work Polyethylene glycol (PEG)-coated gold nano-particles (GNPs) and super paramagnetic iron oxide nano-particles (SPIONs) were investigated as radio-sensitizers for malignant breast (MCF7) cells irradiated by energetic protons. The cells were cultured in the Department of Biology's Cell Culture Laboratory, where they were plated onto either custom 15-well plates or standard 96-well plates 48 hours prior to irradiation. The cells were then irradiated by 3 MeV protons in the East Carolina University Accelerator Laboratory in the Department of Physics. Twenty-four hours prior to irradiation the cells were treated with varying concentrations of the metallic nano-particles (NPs). Cell viability was determined using a color-metric assay (PrestoBlue), which was conducted prior to, as well as 24 hours post irradiation. Survival curves were determined based on the metabolic rate for each NP type and concentration post irradiation to observe potential sensitization effects. Sensitization effects were only observed for the PEG-coated GNPs at concentrations of 15 nM, 45 nM, and 68 nM. While each showed promise as radio sensitizers at the higher dose ranges (>6 Gy), the 45 nM concentration showed the greatest sensitization effects throughout the entire dose range (2-11 Gy).