X-ray radiation enhancement of gold- TiO2 nanocomposites

Abstract

The interaction of ionizing radiation, such as X-rays, with materials at the nanoscale, holds promising applications in various fields, particularly in radiation therapy. In this regard, radiosensitizers are of importance due to their ability to augment cell sensitivity to radiation. Herein, the radiation enhancement response of Gold-titania (Au@TiO2) nanocomposites was evidenced by monitoring the methylene blue (MB) decomposition in the presence of the nanomaterial. This response was investigated for the first time as a function of parameters such as gold loading, TiO2 particle size, ligand used for synthesis, nanocomposite concentration, irradiation voltage, and dose rate. Au@TiO2 were fabricated by X-rays radiolytic synthesis, a method carried out at room temperature and pressure, in the absence of toxic chemicals, which is fundamental for medical applications. Results showed that the addition of Au@TiO2 to MB accelerates the dye reaction rate by increasing the number of reactive oxygen species in solution. Reaction rate enhancements ranging from ~40% to 78% were observed in the presence of Au@TiO2. The highest values were achieved when using TiO2 with 6.5 nm in particle size, 10% Au loading, and NaOH as the ligand. This combination of parameters led to an increase in the number of active sites in the nanomaterial, facilitating MB decomposition. Au@TiO2 radiosensitization was also tested in a biological environment with M. aeruginosa cells. The presence of the NCs during irradiation notoriously increased cell damage. Overall, Au@TiO2 have great promise as radiosensitizers, a feature that could be relevant to a number of medical, biological and environmental applications.