AIE-active Ir(iii) complexes as type-I dominant photosensitizers for efficient photodynamic therapy. Issue 4 (5th January 2023) - Tong, Jialin
Abstract : Four new AIE-active Ir(iii ) complexes were synthesized. MFIrqa, SFIriqa and SFIrqa based NPs are shown to be good PSs in vitro for PDT through Type I ˙OH generation mechanism. Abstract : The ability of a photosensitizer (PS) to generate reactive oxygen species (ROS) including type I oxygen free radicals and type II 1 O2 is pivotal for photodynamic therapy. Luminescent Ir(iii ) complexes are effective PSs with high 1 O2 generation ability owing to their high intersystem crossing ability and effective energy transfer to 3 O2 . However, so far, reports on type I ROS based on ˙OH generation induced by Ir(iii ) PS are still rare. In this work, four novel aggregation-induced emission (AIE)-active Ir(iii ) PSs, namely MFIriqa, MFIrqa, SFIriqa, and SFIrqa have been designed and synthesized, which show highly efficient emission in the aggregated state. Cell imaging experiment results indicate that all four Ir(iii ) PSs can effectively improve the signal-to-noise ratio of imaging by reducing the interference from the background due to their fascinating AIE properties. Importantly, in vitro, Ir(iii ) PSs MFIrqa, SFIriqa, and SFIrqa nanoparticles show obvious photodynamic activity toward cancer cells upon irradiation accompanied by type I ˙OH generation, which may be attributed to the unique excited-state characteristics of Ir(iii ) complexes. This work will provide guidance for the construction of a type I photosensitizer based on the AIE-active Ir(iii ) complex, which offers great advantages for potential clinical applications under hypoxic conditions.