Hydrated electron yield enhancing by Gd nanoparticles under X-rays beams: an in-line fluorescence study

Nanoparticles can be used to enhance the effect of the dose delivered by the ionizing beam in cancer therapy. [1][2] In this framework, we have studied the formation of hydrated electrons yield formation under X-ray beams in the presence of NP by using resazurin molecule in de-aerated water. The method lays on the detection of resorufin (RN) fluorescence. This species is the product of the resazurin reduction by hydrated electron. Fluorescence spectroscopy is performed in line with X-ray beam using real-time emission detection and a 532nm-CW laser as an excitation source. Experiments were performed at the ESRF synchrotron in the biomedical ID17 room with an X-ray energy ranging between 45 keV and 90 keV, around the K-edge of Gd. The results show an increase of the resorufin yield formation in the presence of Gd nanoparticles. Furthermore, the RN radiolytic yield increases with the increase of Gd nanoparticles concentration. We further demonstrated that resazurin reduction depends on the dose rate. As shown in the figure below, the concentration of RN at a fixed absorbed dose increases at lower dose rates. For the future work, we intend to repeat this experiment by irradiating with high-energy electrons and alpha particles. References [1] – M. Y. Chang, A. L. Shiau, Y. H. Chen, C. J. Chang, H. H-W Chen and C. L. Wu. Cancer Science. 99(7), 1479, (2001). [2] – A. Mesbahi. Reports of pratical Oncology & Radiotherapy. 15(6), 176, (2010).