Radiotherapy’s lack of selectivity can be potentially overcome by enhancing the local deposited radiation dose in the tumour leading to increased cell killing and tumour reduction. This can be accomplished using gold or gadolinium nanoparticles as these enhance cell sensitivity to radiation (radiosensitization) given their ability to absorb more energy per unit mass compared to soft tissues. As a result of this property more energy is deposited in the tissue where nanoparticles are present potentially allowing the reduction of dose delivered thus sparing normal tissue and reducing side effects.
Here we use gold nanoparticles or a combination of gold and gadolinium with different coatings to determine their radiosensitization potential, toxicity and DNA damage in several prostate cancer cell lines. We found that gold nanoparticles can induce DNA damage directly and there is a cell line dependent increase of DNA damage after continuous exposure. Moreover, cells exposed to radiation together with gold nanoparticles appear to have different DNA double-strand break repair kinetics.
The different coated NPs were tested regarding their toxicity during short and prolonged exposures in prostate cancer cell lines indicating coating and cell line dependent toxicity. Furthermore some of these NPs were found to influence metabolic activity leading to a decrease in proliferation rate.
Their radiosensitizing ability has also been related to the coating with different radiosensitizing level associated to each NP. Despite the need for further characterization and better understanding of the nanoscale processes influencing cellular response in the presence of NPs, one NP has been identified as a potential radiosensitizer given its low toxicity and high sensitizing effect.