Preliminary study on singlet oxygen production using CeF3:Tb3+@SiO2-PpIX

• CeF3:Tb3+ nanoparticles were prepared via sol–gel route.
• Surface modification by SiO2 layer and bioconjugation with PpIX were performed.
• Radioluminescence spectra indicate an energy transfer from Tb3+ to PpIX.
• X-ray-induced singlet oxygen production was observed.

Luminescent properties and singlet oxygen production using CeF3:Tb3+-based nanoparticles modified with SiO2 and protoporphyrin IX (PpIX) were studied. CeF3:Tb3+ nanopowder was prepared via sol–gel route, with subsequent surface coating by SiO2 layer and the conjugation with photosensitive PpIX molecules. Radioluminescence spectra suggest an energy transfer from Ce3+ to Tb3+ ions and from Tb3+ to molecules of PpIX photosensitizer. The energy transfer was confirmed by photoluminescence decay curves. Singlet oxygen production was detected using a reaction of 1O2 with 3’-(p-aminophenyl) fluorescein (APF) chemical probe after X-Ray excitation. Qualitative changes in time resolved photoluminescence spectra in the region of 520 nm indicate 1O2 generation. Studied nanocomposites may be good candidates for the application in X-ray induced photodynamic therapy.