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Hybrid TiO 2 –Ruthenium Nano‐photosensitizer Synergistically Produces Reactive Oxygen Species in both Hypoxic and Normoxic Conditions
Author(s) -
Gilson Rebecca C.,
Black Kvar C. L.,
Lane Daniel D.,
Achilefu Samuel
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201704458
Subject(s) - photosensitizer , reactive oxygen species , radical , hydrogen peroxide , photochemistry , chemistry , photodynamic therapy , oxygen , ruthenium , hydroxyl radical , nanoparticle , catalysis , materials science , nanotechnology , organic chemistry , biochemistry
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 TiO 2 nanoparticle afforded TiO 2 ‐N3. Upon exposure of TiO 2 ‐N3 to light, the N3 injected electrons into TiO 2 to produce three‐ and four‐fold more hydroxyl radicals and hydrogen peroxide, respectively, than TiO 2 at 160 mmHg. TiO 2 ‐N3 maintained three‐fold higher hydroxyl radicals than TiO 2 under hypoxic conditions via N3‐facilitated electron–hole reduction of adsorbed water molecules. The incorporation of N3 transformed TiO 2 from a dual type I and II PDT agent to a predominantly type I photosensitizer, irrespective of the oxygen content.