A two-photon AIE fluorophore as a photosensitizer for highly efficient mitochondria-targeted photodynamic therapy

Nowadays, photodynamic therapy (PDT) has become an effective way for cancer therapy. However, there are still some drawbacks for common photosensitizers including poor photostability, nonspecific targeting, poor penetration depth of tissue and low PDT efficiency etc. Therefore, the development of high-performance photosensitizers is highly desirable. In this study, we design an aggregation-induced emission (AIE) photosensitizer TBBP based on a D-π-A skeleton. This photosensitizer TBBP exhibits strong aggregation-induced emission, large two-photon absorption cross-section, high specificity to mitochondria, deep tissue imging with a penetration depth up to 150 μm and excellent biocompatibility, showing great potential as a bioprobe in two-photon cell and tissue bioimaging. Furthermore, a higher PDT efficiency than the most commonly used commercial photosensitizer Ce6 has been shown for TBBP owing to the efficient 1O2 generation, high 1O2 quantum yield as well as the enhanced endocytosis. The two-photon cell and deep tissue bioimaging and highly efficient mitochondria-targeted photodynamic therapy make this AIE fluorophore TBBP grerat potential in the clinical application.