Synchrotron-Based Infrared Microscopy Studies of the Radiosensitization Effects of Nanoparticles used in Radiotherapy

Abstract

Radiotherapy (RT) is the most important non-surgical modality for cancer and the recent technological advances brought a substantial gain in the balance between the probability of tumor control and the risk of normal tissue complications. However, the clinical management of some radioresistant tumors (such as brain gliomas) continues being a challenge since tumor doses are constrained by the surrounding healthy tissue tolerances. Within this context, new modalities such as radiosensitization in the presence of high atomic number nanoparticles (NP) are extensively evaluated, with the main goal of enhancing the differential effect between tumors and healthy tissues. In the present work, Synchrotron based Fourier Transform Infrared Microspectroscopy (SR-FTIRM), a vibrational spectroscopic technique for the biochemical cell analysis on a microscopic scale, provides relevant information on the treatment-induced modifications of the main biomolecules (nucleic acids, proteins and lipids). A series of treatments, including various NP sized, typed and chemical natured (3 nm gadolinium (GdNP), 1.9 nm gold (AuNP) nanoparticles), cell line used (F98 murine and U87-MG human glioma cells) and radiotherapy configuration (megavoltage X-ray photon energy (MV) normaly used in clinics, with respect to kilovoltage photons (kV)), were assessed for their induced cell macromolecular damages (Martinez-Rovira et al. (2019) Analyst 144, 5511 and DOI: 10.1039/c9an01109a). Additionally, alongside X-ray photon RT, the possible cell damages caused by several charged particle beams (proton, helium, carbon and oxygen) were also considered. Briefly, the biochemical information provided by the highly brilliant infrared light source produced at ALBA Synchrotron leads to a clear advantage in spectral quality at a cellular level and allow better characterization of NP induced damage in cells.