A lysosomes and mitochondria dual-targeting AIE-active NIR photosensitizer: Constructing amphiphilic structure for enhanced antitumor activity and two-photon imaging

Development of lysosomes and mitochondria dual-targeting photosensitizer with the virtues of near-infrared (NIR) emission, highly efficient reactive oxygen generation, good phototoxicity and biocompatibility is highly desirable in the field of imaging-guided photodynamic therapy (PDT) for cancer. Herein, a new positively charged amphiphilic organic compound (2-(2-(5-(7-(4-(diphenylamino)phenyl)benzo[c] [1,2,5]thiadiazol-4-yl)thiophen-2-yl)vinyl)-3-methylbenzo[d]thiazol-3-ium iodide) (ADB) based on a D-A-π-A structure is designed and comprehensively investigated. ADB demonstrates special lysosomes and mitochondria dual-organelles targeting, bright NIR aggregation-induced emission (AIE) at 736 nm, high singlet oxygen (1O2) quantum yield (0.442), as well as good biocompatibility and photostability. In addition, ADB can act as a two-photon imaging agent for the elaborate observation of living cells and blood vessel networks of tissues. Upon light irradiation, obvious decrease of mitochondrial membrane potential (MMP), abnormal mitochondria morphology, as well as phagocytotic vesicles and lysosomal disruption in cells are observed, which further induce cell apoptosis and resulting in enhanced antitumor activity for cancer treatment. In vivo experiments reveal that ADB can inhibit tumor growth efficiently upon light exposure. These findings demonstrate that this dual-organelles targeted ADB has great potential for clinical imaging-guided photodynamic therapy, and this work provides a new avenue for the development of multi-organelles targeted photosensitizers for highly efficient cancer treatment.