Using rare-earth based nanoscintillators for X-ray induced photodynamic therapy

Pancreatic cancer is associated with a poor prognosis despite multimodal treatments consisting in surgery, chemotherapy and radiotherapy. Photodynamic therapy (PDT) is a promising treatment that aims to activate photosensitizers with light in order to induce local cell damage. However, its use for treating deep tumors, including pancreatic tumors, is limited because of the low penetration depth of light in tissues. To overcome this limitation, it has been proposed to use nanoscintillators (NS) that down-convert ionizing radiation such as X-rays used in radiotherapy, into UV-visible photons. These nanoparticles could improve the efficacy of radiotherapy through at least three effects: the radiation dose-enhancement effect1 that is a physical effect due to the accumulation of heavy elements in the vicinity of tumors, the emission of UV-C photons that increase direct DNA damage, and the activation of photodynamic therapy by X-rays (X-PDT)2. The aim of our project is to conjugate NS with appropriate photosensitizers to achieve PDT during radiotherapy.