Structural Modification Orientated Multifunctional AIE Fluorescence Probes: Organelles Imaging and Effective Photosensitizer for Photodynamic Therapy

Luminogens with aggregation-induced emission feature (AIEgens) are highly demanded because of its excellent performance in fluorescent bioprobes. In this work, three AIEgens based on tetraphenylethylene isoquinolinium (TPE-IQ) derivatives by introducing different electron donor and sterically hindered groups to replace the phenyl ring of the isoquinolinium core are prepared in a one-pot reaction with a high yield and characterized systematically. By the analysis of photophysical properties and theoretical calculations, the structure-property relationships among them become clear. Although they all inherit AIE feature as expected, these similar structural AIEgens present different organelle-targets, which is attributed to their different cellular uptake way and energy barrier to cell membrane by detailed experiments. In addition, these TPE-IQ-based AIEgens are potential candidates for photodynamic therapy originating from their activities of generating reactive oxygen species under visible light irradiation.