Intramolecular Charge Transfer (ICT) Based Two-photon Fluorescent Probe for Bisulfite with Bioimaging Applications

A two-photon fluorescent probe has been adopted for bisulfite based on an intramolecular charge transfer (ICT) mechanism. The fluorescence intensity of the probe decreased by 837 fold following treatment with HSO3− and the detection limit was 42 nM. This probe showed excellent properties such as high photostability, good two-photon properties, and large Stokes shifts. More importantly, this approach offers a rapid, highly selective, and sensitive method to determine HSO3− in buffer solutions and real samples. Furthermore, the probe was successfully used for two-photon fluorescence visualization of trace SO2 derivatives in biological systems.