Hybrid TiO2 -Ruthenium Nano-photosensitizer Synergistically Produces Reactive Oxygen Species in both Hypoxic and Normoxic Conditions.

ABSTRACT: Photodynamic therapy (PDT) is widely used to treat diverse diseases, but its dependence on oxygen to produce cytotoxic reactive oxygen species (ROS) diminishes the therapeutic effect in a hypoxic environment, such as solid tumors. Herein, we developed a ROS-producing hybrid nanoparticle-based photosensitizer capable of maintaining high levels of ROS under both normoxic and hypoxic conditions. Conjugation of a ruthenium complex (N3) to a TiO2 nanoparticle afforded TiO2 -N3. Upon exposure of TiO2 -N3 to light, the N3 injected electrons into TiO2 to produce three- and four-fold more hydroxyl radicals and hydrogen peroxide, respectively, than TiO2 at 160?mmHg. TiO2 -N3 maintained three-fold higher hydroxyl radicals than TiO2 under hypoxic conditions via N3-facilitated electron-hole reduction of adsorbed water molecules. The incorporation of N3 transformed TiO2 from a dual type?I and II PDT agent to a predominantly type?I photosensitizer, irrespective of the oxygen content.

SUBMITTER: Gilson RC 

PROVIDER: S-EPMC5749187 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature