The Rare-Earth Elements Doping of BaGdF5 Nanophosphors for X-ray Photodynamic Therapy

It is known that the initiation of photodynamic therapy (PDT) in deep-seated tumors requires the use of X-rays to activate the reactive oxygen species generation in deep tissues. The aim of this paper is to synthesize X-ray nanophosphors and analyze their structural and luminescence characteristics to push the PDT process deep into the body. The article deals with BaGdF5:Eu3+, BaGdF5:Sm3+, and BaGdF5:Tb3+ nanophosphors synthesized using microwave synthesis. It is found that the nanoparticles are biocompatible and have sizes 5–17 nm. However, according to the analysis of X-ray excited optical luminescence, BaGdF5:Sm3+ nanophosphors will not be effective for treating deep-seated tumors. Thus, BaGdF5:Eu3+ and BaGdF5:Tb3+ nanoparticles meet the requirements for the subsequent production of nanocomposites based on them that can be used in X-ray photodynamic therapy.

Combining X-ray excited optical luminescence and X-ray absorption spectroscopy for correlative imaging on the nanoscale

X-ray absorption and optical luminescence can both provide valuable but very different information on the chemical and physical properties of materials. Although it is known that the spectral characteristics of many materials are highly heterogeneous on the micro- and/or nanoscale, no methodology has so far been shown to be capable of spatially resolving both full X-ray absorption and X-ray excited optical luminescence (XEOL) spectra on the nanoscale in a correlative manner. For this purpose, the scanning transmission X-ray microscope at the HERMES beamline of the SOLEIL synchrotron was equipped with an optical detection system capable of recording high-resolution XEOL spectra using a 40 nm soft X-ray probe. The functionality of the system was demonstrated by analyzing ZnO powder dispersions — showing simultaneously the X-ray linear dichroism and XEOL behavior of individual submicrometric ZnO crystallites.