Monoamine oxidase A probe synthesis and fluorescence imaging in cells and zebrafish based on AIE mechanism

Monoamine oxidase A (MAO-A) is a crucial mammalian flavoenzyme that plays a significant role in various neurodegenerative diseases such as depression, Parkinson’s disease, schizophrenia, and epilepsy, as well as cancer, cardiac disorders, and liver disease. Thus, a real-time and targeted MAO-A detection approach is desperately needed to study the onset and management of disorders linked to MAO-A. In this study, we have successfully synthesized a red-emitting fluorescent probe AIE-M, which is based on the specificity of MAOs for the structural catalysis of propylamine group substrates. This probe utilizes quinoline-malononitrile (QM) with AIE properties as the fluorescent master. The probe containing QM exhibits excellent aggregation-induced luminescence (AIE), biocompatibility, and high photostability, enabling specific recognition of MAO-A. Moreover, it can be employed for the detection and imaging of endogenous MAO-A in neuroblastoma cells and zebrafish, thereby offering a novel research instrument for diagnosing associated ailments. [Display omitted] •The AIE-M probe tracks MAO-A activity in situ and has large Stokes shift, low cytotoxicity, and high sensitivity.