An AIE Photosensitizer with Simultaneous Type Ⅰ and Type Ⅱ ROS Generation: Efficient Bacterial Elimination and Hypoxic Tumor Ablation

摘要

Aggregation induced emission (AIE) photosensitizers have attracted greatattention due to their good performance in photodynamic therapy (PDT).However, the therapeutic effect of AIE photosensitizer is often highlydependent on the biological microenvironment because it is difficult to producetype Ⅰ and type Ⅱ reactive oxygen species (ROS) simultaneously. Herein,an electron-rich anion-π+ AIEgen Pys-QM-TT is reported, which is capable ofhighly generating type Ⅰ and type Ⅱ ROS and realizing near-infrared fluorescenceimaging synchronously. In the rational design of AIE photosensitizer,the strong electron-donating triphenylamine unit, π-bridge thiophene andelectron-withdrawing pyridinium salt unit can enhance the D–π–A behavior,thereby improving the intramolecular charge transfer effect and extendingthe wavelength. Meanwhile, the powerful D–π–A effect is supposed to reduceΔE_(S-T) and promote the intersystem crossing processes, thus increasing thegeneration of ROS. In addition, the negatively charged anion in pyridiniumsalt group provides an electron-rich environment for the excited photosensitizer,so as to promote electron transfer to generate type I ROS. Therefore,Pys-QM-TT can not only generate type Ⅰ and type Ⅱ ROS simultaneously withweak environmental dependence, but also effectively inhibit bacterial infectionsand ablate tumor tissue by promoting tumor cell apoptosis, inhibitingtumor cell proliferation and anti-angiogenesis.