A lysosomal targeted fluorescent probe based on BODIPY for monitoring NO in living cells and zebrafish imaging

Nitric oxide (NO), as a special biological small molecule, plays an important role in physiology and pathology. Studies have revealed a strong correlation between human illness and the amount of NO in lysosomes. In this research, we synthesized a BODIPY-based fluorescent probe BML that can be localized in the lysosome to detect NO. The secondary amine in the BML structure can be N-nitrosation reaction with NO in the lysosome, preventing the initial photo-induced electron transfer (PET) process and leading to the creation of the highly luminescent BML-NO. The reaction mechanism was proved in the high-resolution mass spectrometry and DFT simulation calculations. Additionally, BML was discovered to have some evident benefits, such as fast detection time (3.5 min), low detection limit (LOD = 10.3 nM), and the resistance to interference and acidity, which are essential for the detection of NO in lysosomes. Furthermore, the BML was effectively employed to detect endogenous and exogenous nitric oxide in living cells and zebrafish.