A biomarker (ONOO-)-activated multicolor fluorescent probe for early detection and assessment of arthritis

To understand the entangled relationship between reactive oxygen species (ROS) and arthritis, it is of great interest to urgently need an effective bioanalytical method to detect biomarker peroxynitrite (ONOO-) of arthritis in vivo. In contrast to the previously reported ONOO- fluorescent probes, multicolor fluorescent probe could be applied to complex environments for multi-component analysis and provide multichannel imaging results. However, multicolor fluorescent probes for ONOO- detecting have not been reported so far. Herein, an ONOO-- activated multicolor fluorescent probe (MULTI-ONOO) based on FRET was developed for quantitative detecting and visualization of ONOO- levels in arthritis. This probe mainly contained an acceptor (near-infrared xanthane fluorophore) and a donor (naphthalimide fluorophore). In the presence of ONOO-, the oxonium ion undergoes a strong nucleophilic response between ONOO- and xanthane to generate coumarin (CM) and naphthimide (NP) fluorophores with multicolor signal output. Impressively, MULTI-ONOO has a rapid response time (~20 s) and outstanding detection limits as low as 11.6 nM. Finally, this probe was successfully adopted to detect endogenous ONOO- in living cells, arthritis tissues and rat model. Thus, this ONOO--activated multicolor probe could provide a robust tool for investigating the role of ONOO- between in different inflamed diseases.