Mesoporous ZnO integrated CeF3 nanoparticles for X-ray PDT

Abstract

We report a modified two stage method to develop CeF₃ embedded mesoporous ZnO nanostructures for the X-ray arbitrated photodynamic therapy (X-ray PDT) to enhance therapeutic efficacy. X-ray and electron diffraction patterns confirmed the phases of CeF₃-ZnO nanocomposite. Transmission electron microscopy (TEM) revealed the morphologies and sizes for both the phases i.e. CeF₃ (5–10 nm) and ZnO (150–250 nm) in the nanocomposite. Photoluminescence spectroscopy was employed to probe their energy emission and absorption characteristics of the CeF₃-ZnO mesoporous nanocomposite. Moreover, a strong emission characteristic of Zn²⁺ ions via energy transfer from Ce³⁺ ions is proposed by energy transfer mechanism. The colloidal stability, hydrodynamic size, and surface charge distribution of the nanocomposite were analyzed using dynamic light scattering (DLS) for size measurement and a Zetasizer for surface charge evaluation. X-ray photoelectron spectroscopy (XPS) demonstrated the various oxidation states of each element (i.e. Ce, F, Zn and O) present in the nanocomposite sample. The BET-specific surface area was determined to be significantly high, approximately 68 m²/g, with a narrow pore size distribution and an average pore size of around 36.7 nm. The biocompatibility studies using the MTT assay on human lung adenocarcinoma alveolar basal epithelial cells (A549) demonstrated the more than 80 % cell viability at a concentration 50 μg/ml. These results highlight the potential of mesoporous ZnO embedded CeF₃ nanoparticles as an effective platform for enhanced X-ray PDT.