Surface modifications of gold-nanoparticles to enhance radiation cytotoxicity

We successfully synthesized gold nanoparticles (GNPs) modified with two kinds of functional molecules, Cysteamine (AET) and thio-glucose (Glu). We also studied their cell uptake and radiation cytotoxicity enhancement in the breast and pancreatic cancer cells. Our Transmission Electron Microscopy (TEM) results showed that cancer cells uptake functional Glu-GNPs significantly more than naked GNPs. The TEM results also indicated that AET-capped GNPs were mostly bound to the MCF-7 cell membrane while Glu-GNPs entered the cells and were distributed in the cytoplasm. After the cancer cell uptaking of Glu-GNPs, or binding of AET-GNPs, the in vitro cytotoxicity effects were determined at 24, 48 and 72 hours, respectively. The results showed that these functional GNPs had little or no toxicity to these cells. We applied various forms of irradiation, such as 200 kVp X-rays and gamma-rays, to the target cells, either with or without functional GNPs. By comparison with irradiation alone, our results showed that the GNPs could significantly enhance cancer killing induced by irradiation.