LAUSR

The peroxynitrite ion (ONOO- ) has important roles in many biological processes. We have developed a multicolor ONOO- -sensing probe (SiONNOH) that undergoes deprotonation and desilylation processes, which result in several changes in the emission wavelengths. In response to different concentrations of ONOO- , the probe exhibits fluorescence changes from pink (595 nm at 2 eq. ONOO- ) to green (540 nm at 6 eq. ONOO- ) via orange (3 eq. ONOO- ) and yellow (4 eq. ONOO- ) under physiological conditions until no fluorescence signal is observed after ONOO- is completely eliminated by lipoic acid. The probe shows the high selectivity for ONOO- and the limit of detection is calculated to be 1.27 μM. Moreover, the probe shows the capacity to monitor the concentration ranges of ONOO- through multicolor fluorescence in living cells, which will greatly facilitate the rapid detection of ONOO- concentration ranges by the naked eye under a UV light without any precision instrumentation.