title: In vivo demonstration of enhanced radiotherapy using rare earth doped titania nanoparticles.
abstract: Radiation therapy is often limited by damage to healthy tissue and associated side-effects; restricting radiation to ineffective doses. Preferential incorporation of materials into tumour tissue can enhance the effect of radiation. Titania has precedent for use in photodynamic therapy (PDT), generating reactive oxygen species (ROS) upon photoexcitation, but is limited by the penetration depth of UV light. Optimization of a nanomaterial for interaction with X-rays could be used for deep tumour treatment. As such, titania nanoparticles were doped with gadolinium to optimize the localized energy absorption from a conventional medical X-ray, and further optimized by the addition of other rare earth (RE) elements. These elements were selected due to their large X-ray photon interaction cross-section, and potential for integration into the titania crystal structure. Specific activation of the nanoparticles by X-ray can result in generation of ROS leading to cell death in a tumour-localized manner. We show here that intratumoural injection of RE doped titania nanoparticles can enhance the efficacy of radiotherapy in vivo.
authors: Department of Engineering Science, Oxford University, Oxford, UK. Helen.Townley@eng.ox.ac.uk
authors: Helen E
authors: HE
authors: Townley
authors: Jeewon
authors: J
authors: Kim
authors: Peter J
authors: PJ
authors: Dobson
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D045744:Cell Line, Tumor; D005682:Gadolinium / Q000737:chemistry; D056945:Hep G2 Cells; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000627:therapeutic use / Q000633:toxicity; D008674:Metals, Rare Earth / Q000737:chemistry*; D051379:Mice; D009369:Neoplasms / Q000532:radiotherapy; D017382:Reactive Oxygen Species / Q000378:metabolism; D014025:Titanium / Q000737:chemistry*; D014183:Transplantation, Heterologous; D014466:Ultraviolet Rays; D014965:X-Rays
chemical_list: D008674:Metals, Rare Earth; D017382:Reactive Oxygen Species; C009495:titanium dioxide; D005682:Gadolinium; D014025:Titanium