A Sequentially activated probe for simultaneous fluorescence imaging of ONOO― and HOBr in brain to indicate Alzheimer’s Disease

Alzheimer's disease (AD) is an irreversible neurodegenerative disorder characterized by progressive cognitive decline and memory loss. However, clinical diagnosis is only effective for patients with obvious clinical symptoms, which cannot provide precise diagnosis in the early stages of AD. Therefore, developing a practical tool for rapid and accurate diagnosis of AD is of paramount importance. Research suggests that reactive oxygen species (ROS), specifically peroxynitrite (ONOO ― ) and hypobromous acid (HOBr), may involve in the progression of AD, which could serve as biomarkers. Research on the simultaneous imaging of two kinds of ROS in AD using a single fluorescence probe remains sparse. To enhance diagnostic accuracy, our research designed an ingenious small-molecule fluorescent probe, NBO, for the sequential detection of ONOO ― and HOBr with distinguishable spectra. By utilization of NBO, elevated ONOO ― and HOBr levels were found in AD brain, and the therapeutic efficacy of AD drugs were successfully assessed.