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

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. - Highlights: • 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.