title: Cerium oxide nanoparticles: influence of the high-Z component revealed on radioresistant 9L cell survival under X-ray irradiation.
abstract: This article pioneers a study into the influence of the high-Z component of nanoparticles on the efficacy of radioprotection some nanoparticles offer to exposed cells irradiated with X-rays. We reveal a significant decrease in the radioprotection efficacy for cells exposed to CeO2 nanoparticles and irradiated with 10 MV and 150 kVp X-rays. In addition, analysis of the 150 kVp survival curve data indicates a change in radiation quality, becoming more lethal for irradiated cells exposed to CeO2 nanoparticles. We attribute the change in efficacy to an increase in high linear energy transfer Auger electron production at 150 kVp which counterbalances the CeO2 nanoparticle radioprotection capability and locally changes the radiation quality. This study highlights an interesting phenomenon that must be considered if radiation protection drugs for use in radiotherapy are developed based on CeO2 nanoparticles.
  
  
  BACKGROUND
  CeO2 nanoparticles are thought to offer radioprotection; however, this study reveals significant decrease in the radioprotection efficacy for cells exposed to CeO2 nanoparticles and irradiated with 10 MV and 150 kVp X-rays. This phenomenon must be considered when developing radiation protection drugs based on CeO2 nanoparticles.
authors.affiliation: Centre for Medical and Radiation Physics, University of Wollongong, NSW, Australia; Illawarra Health and Medical Research Institute, University of Wollongong, NSW, Australia.
authors.forename: Adam
authors.initials: A
authors.lastname: Briggs
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Corde
authors.forename: Sianne
authors.initials: S
authors.lastname: Oktaria
authors.forename: Ryan
authors.initials: R
authors.lastname: Brown
authors.forename: Anatoly
authors.initials: A
authors.lastname: Rosenfeld
authors.forename: Michael
authors.initials: M
authors.lastname: Lerch
authors.forename: Konstantin
authors.initials: K
authors.lastname: Konstantinov
authors.forename: Moeava
authors.initials: M
authors.lastname: Tehei
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D002563:Cerium / Q000494:pharmacology* / Q000633:toxicity; D002999:Clone Cells; D004583:Electrons; D053758:Nanoparticles / Q000737:chemistry* / Q000633:toxicity / Q000648:ultrastructure; D011836:Radiation Tolerance / Q000187:drug effects* / Q000528:radiation effects*; D051381:Rats; D014961:X-Ray Diffraction; D014965:X-Rays
chemical_list: D002563:Cerium; C030583:ceric oxide
keywords: Cerium oxide nanoparticles; High-Z; Photoelectric effect; Radioprotectors; Radioresistant