Radiation Enhancement with Polyethyleneimine-Coated Gold Nanoparticles Under MV Photons

Abstract

OBJECTIVERadiotherapy 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 doselimiting in terms of acute and late toxicity. Radiosensitizers (RSs) can be used to enhance intratumoraldose, thus improving the therapeutic ratio. We aimed to investigate the cytotoxicity on normal andcancer cell lines induced by interaction between MV photon irradiation and polyethyleneimine (PEI)-coated gold nanoparticles (AuNPs).METHODSThe effects of different concentrations of AuNPs (0.75 µg/ml, 0.5 µg/ml, 0.25 µg/ml, and only medium)and 2 Gy ionizing radiation (IR) were investigated on the L929 fibroblast, DLD-1 colon, and H1299 lungcancer cell lines. Cytoplasmic and nuclear membranes treated with hematoxylin and eosin and doublestaining were evaluated with light and fluorescence microscopy. Cytotoxicity was determined with theWST-1 method.RESULTSAll particles were spherical in shape with 60.98 nm in size. Cell surviving ratios without AuNPs were96.34% in L929, 89.68% in DLD-1, and 76.93% in H1299 for a single 2-Gy radiation. These ratios were94.2%, 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 µg/ml, 0.5 µg/ml, and 0.75 µg/ml AuNPs,respectively.CONCLUSIONAt increased concentrations, isolated unwanted cytotoxic effects of AuNPs could be observed. Radiosensitizing effect of PEI-coated AuNPs depends on cell type and AuNP concentration.