Despite major advances in the field of radiotherapy, healthy tissue damage continues to constrain the dose that can be prescribed in cancer therapy. Gold nanoparticles (GNPs) have been proposed as a solution to minimize radiation-associated toxicities by enhancing the radiation dose delivered locally to tumor cells. In the current study, we investigated the application of third-generation GNPs in two-dimensional (2D) and three-dimensional (3D) cell cultures and whether there is synergy between the nanoparticles and kilo- or mega-voltage radiation to cause augmented cytotoxicity. The 10-nm GNPs were found to be nontoxic in both 2D and 3D in vitro cultures of colon cancer cells at concentrations of up to 10-25 µg/ml. There was a significant increase in cell survival fraction reduction following exposure to 1 Gy of kilo-voltage (18.3%) and 2 Gy of mega-voltage (35.3%) radiation when the cells were incubated with 50 µg/ml of GNPs. The biocompatibility of the GNPs combined with their substantial synergy with radiation encourages further investigations into their application in targeted cancer treatment.
Keywords: colon cancer; gold nanoparticles; magnetic levitation; radiation dose enhancement; three‐dimensional cell culture.