Novel metal oxide nanoparticles and compositions thereof for use as radioenhancers or for visualizing biological tissue

The invention concerns inventive nanoparticles (NPs), their compositions and their use as therapeutic agents in particular in the field of oncology and/or as imaging agents. The NPs are composed of first nanoparticles of at least one high-Z metal oxide material, to which smaller second nanoparticles are covalently bonded at the first nanoparticles' surface. The second nanoparticles are composed of either (a) at least one noble metal or at least one metal oxide, metal sulfide, metal selenide or metal sulfide/selenide that is a Fenton or Fenton-like reaction catalyst. The inventive NPs generate a surprisingly therapeutic effect when exposed to ionizing radiation such as X-Rays, [gamma]-Rays, protons, neutrons, radioactive isotopes and/or electron beams. Thus, the NPs may be used as radioenhancers in the field of oncology. The nanoparticles may also be used as contrast agents.