(615d) Identification of Amino Acids for Templating Gold Nanoparticles Under Low Doses of Ionizing Radiation: From Discovery to Design

Radiotherapy is a complex and efficient technique for the ablation of tumors deep inside the body. Despite improvements in the science and technology in the field of medical radiotherapy, determination of the delivered radiation dose is still a challenge. The current sensors suffer from burdensome operation and complicated fabrication leading to sporadic use in the clinic. This talk focuses on the development of a colorimetric sensor upon exposure to ionizing radiation. Gold salt in the presence of ionizing radiation are reduced to monovalent gold atoms which nucleate and grow into nanoparticles which are finally templated by amino acids. We have screened a total of 32 amino acids for their efficacy in templating and stabilizing gold nanoparticles formed after exposure to ionizing radiation. The sensor assembled in a liquid phase was incorporated in a hydrogel. The hydrogel matrix allows for ease of handling and storage of the nanosensor. Ultraviolet-Visible spectroscopy and ¹H NMR was used to characterize the nanosensor system prior to irradiation. Dynamic light scattering and Transmission Electron Microscopy was used to quantify the size of the nanoparticles formed as a function of radiation dose. The simplicity and the ease in detection coupled with minimal processing required to fabricate the sensor makes it an ideal candidate for routine use during clinical radiotherapy to determine the radiation dose delivered to patients.