Dicyanostilbene-derived two-photon fluorescence probe for lead ions in live cells and living tissues

A novel two-photon fluorescence probe for Pb2+ derived from 4-methyl-2,5-dicyano-4′-amino stilbene as a two-photon fluorophore and bis[2-(2-aminophenylsulfanyls)ethyl]amine as a novel Pb2+ ligand was developed. The probe possesses small molecule size, large two-photon absorption cross-section (1020 GM), noncytotoxic effect, long-wavelength emission at 609 nm, large Stokes shift (209 nm), excellent photostability, moderate water-solubility, good cell-permeability, and pH-insensitivity in the biologically relevant pH range. The probe can selectively detect Pb2+ ions in live cells and living tissues without interference from other metal ions and the membrane-bound probes, and its quenching constant (KSVTP) is 7.58 × 105 M−1.

. Dicyanostilbene-derived two-photon fluorescence probe for lead ions in live cells is developed. The probe exhibits large two-photon absorption cross-section (1020 GM), non cytotoxic effect, excellent photostability and good cell-permeability.Figure optionsDownload as PowerPoint slideHighlights
► We developed a novel two-photon fluorescence probe for Pb2+, and an original Pb2+ ligand of bis[2-(2-aminophenylsulfanyls)ethyl]amine.
► The probe has small molecule size, large TP absorption cross-section (1020 GM), noncytotoxic effect, long-wavelength emission at 609 nm (adjacent to the ideal imaging visual window 650−900 nm), large Stokes shift (209 nm), excellent photostability, moderate water-solubility and good cell-permeability.
► The probe can selectively detect Pb2+ ions in live cells and living tissues at a depth of 120 μm without interference from other metal ions and the membrane-bound probes. It is the first such bioimaging probe for Pb2+ in two-photon fluorescence probes.