Constructing a far-red to near-infrared fluorescent probe for highly specific detection of cysteine and its bioimaging applications in living cells and zebrafish†
Abstract
Cys is a common and important sulfur-containing amino acid in living organisms, whose intracellular level changes are associated with a variety of diseases. To specifically detect Cys without interference from other thiol species has considerable significance. However, only selective fluorescent probes are available for cysteine detection; other thiol species can also have certain interference in the sensing process. Herein, we report an irreversible fluorescent probe for the specific detection of cysteine without interference from other thiol species both in living cells and zebrafish. The FR-NIR-Cys probe exhibits a large emission wavelength shift (up to 84 nm) and a significant ratio fluorescence enhancement (up to 41-fold) in the far-red and near-infrared region. Furthermore, we demonstrate that FR-NIR-Cys with good cell permeability can be employed in the far-red to near-infrared imaging of Cys in living cells and zebrafish.