Aggregation induced emission (AIE) photosensitizers have attracted great attention due to their good performance in photodynamic therapy (PDT). However, the therapeutic effect of AIE photosensitizer is often highly dependent on the biological microenvironment because it is difficult to produce type I and type II reactive oxygen species (ROS) simultaneously. Herein, an electron‐rich anion‐π+ AIEgen Pys‐QM‐TT is reported, which is capable of highly generating type I and type II ROS and realizing near‐infrared fluorescence imaging synchronously. In the rational design of AIE photosensitizer, the strong electron‐donating triphenylamine unit, π‐bridge thiophene and electron‐withdrawing pyridinium salt unit can enhance the D–π–A behavior, thereby improving the intramolecular charge transfer effect and extending the wavelength. Meanwhile, the powerful D–π–A effect is supposed to reduce ∆ES‐T and promote the intersystem crossing processes, thus increasing the generation of ROS. In addition, the negatively charged anion in pyridinium salt 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 with weak environmental dependence, but also effectively inhibit bacterial infections and ablate tumor tissue by promoting tumor cell apoptosis, inhibiting tumor cell proliferation and anti‐angiogenesis.
Photosensitizers equipped with high reactive oxygen species (ROS) generation capability and bright emission are essential for accurate tumor imaging and precise photodynamic therapy (PDT). However, traditional aggregation-caused quenching (ACQ) photosensitizers cannot simultaneously produce desirable ROS and bright fluorescence, resulting in poor image-guided therapy effect. Herein, we report an aggregation-induced emission (AIE) photosensitizer TCM-Ph with a strong donor–π–acceptor (D–π–A) structure, which greatly separates the HOMO–LUMO distribution and reduces the ΔEST, thereby increasing the number of triplet excitons and producing more ROS. The AIE photosensitizer TCM-Ph has bright near-infrared emission, as well as a higher ROS generation capacity than the commercial photosensitizers Bengal Rose (RB) and Chlorine e6 (Ce6), and can effectively eliminate cancer cells under image guidance. Therefore, the AIE photosensitizer TCM-Ph has great potential to replace the commercial photosensitizers.
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