Diaminonaphthalene Boronic Acid (DANBA): New Approach for Peroxynitrite Sensing Site.

Selective detection of reactive oxygen species (ROS) is vital for studying their role in brain diseases. Fluorescence probes can distinguish ONOO species from other ROS; however, their selectivity toward ONOO species depends on the ONOO recognition group. Aryl-boronic acids and esters, which are common ONOO recognition groups, are not selective for ONOO over HO. In this study, we developed a diaminonaphthalene (DAN)-protected boronic acid as a new ONOO recognition group that selectively reacts with ONOO over HO and other ROS. Three DAN-protected boronic acid (DANBA)-based fluorophores that emit fluorescence over visible to near-infrared (NIR) regions, Cou-BN, BVP-BN, and HDM-BN, and their aryl-boronic acid-based counterparts (Cou-BO, BVP-BO, and HDM-BO), were developed. The DANBA-based probes exhibited enhanced selectivity toward ONOO over that of their control group, as well as universality in solution assays and in vitro experiments with PC12 cells. The NIR-emissive HDM-BN was optimized to delineate in vivo ONOO levels in mouse brains with Parkinson's disease. This DAN-protected boronic acid belongs to a new generation of recognition groups for developing ONOO probes, and this strategy could be extended to other common hydroxyl-containing dyes to detect ONOO levels in complex biological systems and processes.