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 H₂O₂. In this study, we developed a diaminonaphthalene (DAN)-protected boronic acid as a new ONOO^- recognition group that selectively reacts with ONOO^- over H₂O₂ 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.