Construction of Triphenylamine-Based Aggregation-Induced Emission Luminogens for Lysosomes Imaging and Its Application in the Photodynamic Therapy of Cancer Cells

Lysosomes are important acidic subcellular organelles whose dysfunction can lead to some related diseases. The development of new lysosome-imaging-guided AIEgens for the photodynamic therapy of cancer cells is important. In this work, two novel organic compounds with AIE characteristics, namely, TPAB-CF₃ and TPAB-diCF₃, were designed and synthesized by introducing the weakly basic morpholinyl moiety with lysosome-targeting ability into a triphenylamine-based luminogen. The distorted spatial feature of TPA and the D₁-D₂-π-A structure of these AIEgens prevented the aggregation-caused quenching of traditional fluorescent molecules and efficiently promoted the separation of the HOMO and LUMO. The outcomes were AIE features and a narrow single-triplet energy gap. Furthermore, TPAB-CF₃ and TPAB-diCF₃ showed bright yellow fluorescence emission peaks at 577 and 601 nm; large Stokes shifts of 234 and 256 nm, respectively; and excellent lysosome-targeted imaging of HeLa cells (Pearson's coefficient = 0.90). In addition to the good ¹O₂-generation ability under light irradiation, these AIEgens achieved the high-efficiency bright lysosome imaging-guided photodynamic killing of cancer cells under white-light irradiation.