Efficient Near-Infrared Photosensitizer with Aggregation-Induced Emission Characteristics for Mitochondria-Targeted and Image-guided Photodynamic Cancer Therapy

Mitochondria-targeted photosensitization provides a facile yet precise therapeutic modality in photodynamic therapy (PDT). Herein, we reported two cationic luminogens (TPE-QN and TPE-DQN) with aggregation-induced emission (AIE) characteristics by integrating the tetraphenylethylene group with quinolinium unit. By expanding the molecular π-conjugation, the emission of TPE-DQN successfully red-shifted to the 650 nm with large Stokes shift (~ 200 nm). Benefited to the good biocompatibility as well as suitable cationic feature, both AIE luminogens (AIEgens) were able to specifically stain the mitochondria in cancer cells, which enabled them to distinguish the cancer cells over normal cells. Both AIEgens also exhibited high signal-to-noise ratio even without washing step and excellent photostability. Moreover, both AIEgens efficiently generated singlet oxygen (1O2) under the white light irradiation while the 1O2 generation efficiency of TPE-DQN reached up to 0.83. The selective cancer cells targeting and high 1O2 generation efficiency allowed TPE-DQN to be an excellent therapeutic agent for the image-guided PDT in cancer cells ablation and tumor inhibition.