Radiation Enhancement with Polyethyleneimine-Coated Gold Nanoparticles Under MV Photons

Abstract

OBJECTIVE Radiotherapy is an essential part of cancer management, and about two-thirds of the patients with cancer receive radiation therapy during their treatment. The healthy structures around the tumor are dose limiting in terms of acute and late toxicity. Radiosensitizers (RSs) can be used to enhance intratumoral dose, thus improving the therapeutic ratio. We aimed to investigate the cytotoxicity on normal and cancer cell lines induced by interaction between MV photon irradiation and polyethyleneimine (PEI)-coated gold nanoparticles (AuNPs). METHODS The effects of different concentrations of AuNPs (0.75 mu g/ml, 0.5 mu g/ml, 0.25 mu g/ml, and only medium) and 2-Gy ionizing radiation (IR) were investigated on the L929 fibroblast, DLD-1 colon, and H1299 lung cancer cell lines. Cytoplasmic and nuclear membranes treated with hematoxylin and eosin and double staining were evaluated with light and fluorescence microscopy. Cytotoxicity was determined with the WST-1 method. RESULTS All particles were spherical in shape with 60.98 nm in size. Cell surviving ratios without AuNPs were 96.34% in L929, 89.68% in DLD-1, and 76.93% in H1299 for a single 2-Gy radiation. These ratios were 94.2%, 62.58%, and 40.52% for L929 cells; 72.70%, 41.15%, and 26.71% for DLD-1 cells; and 34.72%, 28.27%, and 17.84% for H1299 cells at concentrations of 0.25 mu g/ml, 0.5 mu g/ml, and 0.75 mu g/ml AuNPs, respectively. CONCLUSION At increased concentrations, isolated unwanted cytotoxic effects of AuNPs could be observed. Radiosen-sitizing effect of PEI-coated AuNPs depends on cell type and AuNP concentration.