Open-Chain Crown-Ether-Derived Two-Photon Fluorescence Probe for Real-Time Dynamic Biopsy of Mercury Ions

Abstract

A novel two-photon fluorescence probe for Hg2+ derived from bis(styryl)terephthalonitrile, as a two-photon fluorophore, and bis[2-(2-hydroxyethyl sulfanyl) ethyl]amino group (ionophore), as a novel Hg2+ ligand, was developed. The probe possesses small molecule size, large two-photon absorption cross-section (1067 GM) in H2O, non-cytotoxic effect, long wavelength emission at 588 nm, large Stokes shift (121 nm), excellent photostability, high water solubility, good cell permeability, and pH insensitivity in the biologically relevant range. The probe can selectively detect Hg2+ ions in live cells and living tissues without interference from other metal ions and the membrane-bound probes, and its quenching constant is 8.73 × 105 M–1.