Nanomedicine is emerging as promising approach for the implementation of oncological methods. In this review, we describe the most recent methods exploiting heavy nanoparticles and hybrid nanomaterials aiming at improving the traditional X-rays-based treatments. High-Z nanoparticles are proposed as radiosensitizers due to their ability to stop the ionizing radiation and to increase the locally delivered therapeutic dose. Other nanoparticles working as catalysts can generate reactive oxygen species upon X-rays exposure. Thanks to their high toxicity and reactivity, these species promote DNA cancer cells damage and apoptosis. Hybrid nanoparticles, composed by scintillators coupled to organic molecules, are suitable in X-rays activated photodynamic therapy. This work highlights the roles played by the diverse nanoparticles, upon ionizing radiation irradiation, according to their physico-chemical properties, surface functionalization, and targeting strategies. The description of nanoparticle qualities demanded by the oncological nanomedicine is presented in relation to the processes occurring in biological medium when X-ray radiation interacts with heavy nanoparticles, including the scintillation mechanisms, the stopping power amplification, and the disputed modeling of the effective deposit of energy within nanomaterials. The comprehension of these issues in nanomedicine drives the strategies of nanoparticles engineering and paves the way for the development of advanced medical therapies.

This study addresses the relationship between material morphology (size, growth parameters and interfaces) and optical emissions in ZnO through an experimental approach, including the effect of different material dimensions from bulk to nano-size, and different excitations, from optical sources to ionizing radiation. Silica supported ZnO nanoparticles and ligand capped ZnO nanoparticles are synthesized through a sol–gel process and hot injection method, respectively. Their optical properties are investigated by radioluminescence, steady-state and time-resolved photoluminescence, and compared to those of commercial micrometric powders and of a bulk single crystal. The Gaussian spectral reconstruction of all emission spectra highlights the occurrence of the same emission bands for all samples, comprising one ultraviolet excitonic peak and four visible defect-related components, whose relative intensities and time dynamics vary with the material parameters and the measurement conditions. The results demonstrate that a wide range of color outputs can be obtained by tuning synthesis conditions and size of pure ZnO nanoparticles, with favorable consequences for the engineering of optical devices based on this material.