Lanthanide Doped Nanoparticles for X-ray Induced Photodynamic Therapy
Synthesis and Properties of Functional Materials
Physical Chemistry of Solids and Surfaces, Material Characterisation
Final Report Abstract
Radioluminescent (RL) materials can emit light upon excitation with ionizing radiation. Bulk RL materials have found widespread use in several fields, from medical imaging to radiation detection for airport security. There are several properties which can be optimized to obtain materials which are best suited for the desired final application, such as the wavelength of emitted light, chemical stability, and luminescence lifetime. For biomedical applications such as X-ray mediated photodynamic therapy (X- PDT), it is of primary importance to develop nanomaterials which have high emission intensities under clinically-relevant doses of radiation, as well as precise emission wavelengths resonant with the absorption of the photosensitizer employed. The goal of this project is to develop, characterize and investigate Dy3+-doped NaLuF4 RLNPs which are most efficient for XPDT. Thus, a systematic approach to developing efficient, stable NaLuF4:Dy3+, Gd3+ nanoparticles and characterization of their properties was established. Radioluminescent nanoaprticles are assumed to produce singlet oxygen based on a single assay. Within this project we demonstrate that multiple assays are required to confidently determine whether singlet oxygen or other reactive oxygen species are being produced through type I or type II PDT mechanism. Rose Bengal and Merocyanine 540 photosensitizers were loaded into mesoporous silica-coated NaLuF4:Dy3+, Gd3+ nanoparticles and the combination of ABDA, DPBF, and NaN3 assays along with electron paramagnetic resonance were employed to determine that superoxide and hydroxyl radicals were exclusively produced from this system under X-ray excitation. Knowledge of the correct PDT mechanism is crucial for informing what types of disease may be best suited for treatment using PDT nanosystems. The present work provides the demonstration that RB and MC540 loaded NaLuF4: 20% Gd3+; 3% Dy3+ RLNPs systems have great potential for use in activating photodynamic therapy in hypoxic environments.
Publications
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Investigating the reactive oxygen species production of Rose Bengal and Merocyanine 540-loaded radioluminescent nanoparticles, Nanosacle adv., 2021,3, 1375-1381
Nsubuga, Anne; Mandl, Gabrielle A. & Capobianco, John A.
