Ultra-Rapid Detection of Endogenous Nitric Oxide Based on Fluorescent Conjugated Polymers Probe

Nitric oxide (NO) is a celebrated signaling molecule involved in diverse vital physiological and pathophysiological processes. Thus, rapid detection of NO in situ is quite significant due to its large diffusion and short half-time. Herein, a new water-soluble conjugated polymer (PBFB-PDA-NMe₃⁺) with an o-diaminophenyl group in the side chain is designed and synthesized as a fluorescence probe for ultrarapid and sensitive detection of endogenous NO via photoinduced electron transfer (PET) mechanism. In the presence of NO, NO can be specifically trapped by o-diaminophenyl group and react with it to form benzotriazole derivative, which leads to the PET being inhibited. The fluorescence of probe thus significantly turns on. Most importantly, the assay is completed within 1 min without further treatments. Furthermore, this probe can rapidly image intracellular NO in A549 cell and S. aureus bacteria only incubating for 15 min. In addition, this probe is highly selective, which can clearly discriminate NO from other reactive species such as NO₃^-, NO, H₂O₂, ^•OH, GSH, cysteine, and ascorbic acid. Hence, this probe with good water-solubility demonstrates the ultra rapid, sensitive, and selective detection of endogenous NO, which is advantageous to investigate NO-related biological processes.