Synthesis and evaluation of mitochondrion-targeted tetraphenylethylene-based photosensitizer

As typical compounds with aggregation induced emission (AIE) property, tetraphenylethylene-based photosensitizers with unique molecular structures and excellent photophysical properties have been widely applied in the bio-specific imaging, diagnosis, photodynamic therapy (PDT) and other related fields. In this work, we have developed a concise and efficient synthetic route to modify the structure of the AIE photosensitizer PS2, incorporating an aminomethyl side chain at the thiophene terminus. This modification offers a versatile platform for subsequent structural diversification. Following this synthetic strategy, a novel photosensitizer 16 with AIE property was successfully obtained. Compound 16 demonstrated excellent photophysical properties and biocompatibility, along with significantly enhanced singlet oxygen generation under white-light irradiation compared to classical photosensitizer [Ru(bpy)₃]²⁺. Furthermore, compound 16 exhibited mitochondrial targeting capability in A431 cells and demonstrated significant phototoxicity under white-light irradiation. In summary, compound 16 demonstrated promising application potential as a single-molecule AIE photosensitizer in the PDT of skin tumors. We also anticipate that this work can offer valuable experimental insights for the development of ideal photosensitizers.