A Cyclometalated Ir^III Complex as a Lysosome‐Targeted Photodynamic Therapeutic Agent for Integrated Imaging and Therapy in Cancer Cells

Abstract

Organelle-targeted photosensitizers (PSs) having luminescence properties are potential theranostic agents for simultaneous luminescence imaging and photodynamic therapy. Herein, we report a water-soluble luminescent cyclometalated Ir complex, Ir-Bp-Ly, as a lysosome-targeted theranostic probe. Ir-Bp-Ly exhibits exceptional photophysical properties, with good triplet-state quantum yield (0.90), singlet oxygen generation quantum yield (0.71 at pH 4), and long lifetime (1.47 μs). Interestingly, Ir-Bp-Ly localizes mostly in lysosomes due to the presence of morpholine units, suggesting its potential use as a lyso-tracker. Ir-Bp-Ly displays a notable PDT effect in C6 glioma cells, efficiently generating reactive oxygen species owing to close proximity between the energy levels of its triplet state and those of molecular oxygen ( O ). The mechanism of cell death has been studied through caspase-3/7 and flow cytometry analyses, which clearly established the apoptotic pathway.

A photoactive Ir–Pd bimetallic cage with high singlet oxygen yield for efficient one/two-photon activated photodynamic therapy

“…The release of proapoptotic proteins is often induced by apoptosis via an intrinsic pathway with caspase 3/7 as key executors. [26][27][28][29] We use the Caspase-Glo assay to clarify the activation of Caspase 3/7 with the HeLa cells treated by different concentrations of MOC-53 (0.5, 1, and 2 mM) and light irradiation. As shown in Fig.…”

X-ray tomography of cryopreserved human prostate cancer cells: mitochondrial targeting by an organoiridium photosensitiser

“…Cyclometallated organoiridium(III) octahedral complexes are promising photosensitisers for PDT [12][13][14][15][16][17][18][19][20][21][22]. They possess high photostability and long luminescence lifetimes, together with an ability to permeate cells [23], and generate toxic ROS upon irradiation.…”

A DNA and mitochondria dual-targeted photosensitizer for two-photon-excited bioimaging and photodynamic therapy

“…To realize subcellular organelle aggregation, several targeting groups are introduced into the molecular structure of PSs (for example, cationic PSs for mitochondria and morpholine-containing ones for lysosomes). 1,22–27 Among the subcellular organelles, mitochondria play essential roles in various physiological activities of cells. 28 Dysfunctional or abnormal mitochondria can rapidly induce cell apoptosis or death of tumors during the process of PDT.…”