Triarylboron-based fluorescent probe with activatable photosensitivity for lysosomal NO imaging

Abstract

Nitric oxide (NO) is a multifunctional signaling molecule that participates in many important biological processes. In this study, we design and synthesize TAB-3-OD, a fluorescent probe for NO detection, by functionalizing a triarylboron with three o-dianilino groups. Weakly luminescent TAB-3-OD reacts with NO to form highly fluorescent triazole-containing TAB-3-TA, exhibiting a significant spectral blue shift that provides a ratiometric readout. The fluorescence imaging of exogenous and endogenous NO in cells with excellent lysosomal localization is achieved using TAB-3-OD. Unlike poorly photosensitive TAB-3-OD, TAB-3-TA is highly photosensitive and promotes the formation of reactive oxygen species (ROS) when irradiated with very low optical density light (1.2 mW/cm2), confirming that the observed photosensitivity is a consequence of the action of NO. Upon light irradiation,TAB-3-TA produces ROS in cells and induces apoptosis. These results reveal that TAB-3-OD can be applied in the diagnosis and treatment of diseases associated with high NO concentrations.