Pyridinium-substituted tetraphenylethylene salt-based photosensitizers by varying counter anions: a highly efficient photodynamic therapy for cancer cell ablation and bacterial inactivation
Wei Xiong, Lingyun Wang, Xiaoli Chen, Hao Tang, Derong Cao, Guozhen Zhang, Wei Chen
Abstract
Cancer and bacterial infection seriously threaten the health of human beings. The development of an image-guided photosensitizer with a "Two-in-One" function that can be simultaneously used for both efficient cancer cell ablation and rapid bacterial inactivation is highly in demand. In this project, we designed and prepared two aggregation-induced emission luminogens (AIEgens) (called TPEPy-I and TPEPy-PF6) with a strong electron push-pull effect. They have a near-infrared (NIR) emission, a high 1O2 quantum yield up to 0.93 and a fluorescence turn-on effect in mitochondria. Upon white light irradiation, the two mitochondria-targeting AIEgens exhibit a highly efficient photodynamic ablation of HeLa cells as well as excellent photodynamic inactivation of both Gram-positive S. aureus and Gram-negative E. coli. The time-dependent density functional theory (TD-DFT) results indicate that compared to TPEPy-PF6, TPEPy-I can easily produce the triplet state that is a prerequisite for 1O2 formation. Moreover, the positive effect of iodide anions gives TPEPy-I a higher photodynamic efficacy in cancer cell ablation and bacterial inactivation as compared with TPEPy-PF6.