Recent advances in fluorescent probes of peroxynitrite: Structural, strategies and biological applications

Peroxynitrite (ONOO^-), owing to its high oxidative and nitrating stress, is associated with several physiological processes in addition to various pathological processes, including those related to neurodegenerative diseases and cancer. Detection of ONOO^- at the cellular level is of great significance to understand its pathogenesis. To this end, a variety of fluorescent probes based on small molecules and nanoparticles (NPs) have been engineered and applied as excellent tools for imaging of ONOO^- in cells as well as in their diverse biological applications. In this review, we highlight representative cases of fluorescent probes based on recognition mechanism and emphasize their response type (ratiometric, two-photon, long-wavelength/near-infrared, and targeting) in ONOO^- detection in the last five years. We further discuss their design strategy, sensing mechanism, and application in bio-imaging and describe NP-based probes according to diverse nanoplatforms.