A near-infrared fluorescent probe for ratiometric imaging peroxynitrite in Parkinson's disease model

As a regular neurodegenerative disease, Parkinson's disease (PD) brings great pain and heavy economic burden to patients. Peroxynitrite (ONOO^-) have attracted great attention to be a neurotoxicity specie in the pathogenesis of PD. Therefore, understanding the physiological functions of ONOO^- in PD disease is of great importance to the early diagnoses. Unfortunately, it still lacks effective method for detecting ONOO^- in PD model. In this work, a highly sensitivity and selectivity near-infrared ratiometric fluorescent probe (named K-ONOO) was designed for tracking ONOO^- in PD model. K-ONOO exhibited a unique ratiometric response toward ONOO^- due to the fracture of the boronic acid ester group and the principle of ICT resulted in red-shifted spectra. K-ONOO exhibited a quantitative response to ONOO^- (0–15 μM) with a low detection limit (212 nM). K-ONOO can successfully map the changes of endogenous ONOO^- in vivo. The results demonstrated that an elevated degree of ONOO^- is closely correlated with zebrafish under rotenone stimulation. More importantly, H₂S may serve as a neuroprotectant, which helps regulate ONOO^- overexpression and prevent oxidative stress-induced neurodegeneration. The visualization imaging of ONOO^- based on K-ONOO provides an auspicious method for understanding the essential role of ONOO^- during PD disease pathology and early diagnosis.