Abstract: The abnormal expression of monoamine oxidases (MAOs), which distributed on the outer mitochondrial membrane can cause the dysfunction of neurotransmitter delivery and related to mental and neurodegenerative diseases. Therefore, the specific detection of MAOs (MAO-A/B) and the regulation of their activities will contribute to the diagnosis and treatment of neurological diseases. In order to distinguish the two subtypes of MAO-A/B, fluorescence detection and imaging techniques with highly specific and sensitive properties have important biological relevance. Herein, our research group based on the concept of "spatial configuration conversion" have designed the two-photon small molecule fluorogenic probes of U1 and F1, which capable of specific fluorescence "Switch-ON" behaviour, and combined with two-photon fluorescence microscopic imaging technology to realize the activity detection of endogenous MAO-B/A in cells and tissues. It is hoped that this works will benefit the understanding of physiological function about MAOs and developing innovative inhibitors, as well as diagnosing and treating in neurological diseases.

Key words: neurological diseases, monoamine oxidases, fluorescent probe, activity detection