A new “on–off” fluorescent probe for the selective detection of copper ions in living cells

Abstract

A new “on–off” fluorescent probe 4′,5′-bis((bis(thiophen-2-ylmethyl)amino)methyl)-2′,7′-dichloro-3′,6′-dihydroxy-3H-spiro[isobenzofuran-1,9′-xanthen]-3-one (probe F) for the selective detection of copper ions was synthesized and characterized. The favorable features of the proposed probe included good selectivity, high sensitivity, excellent water solubility, low toxicity, and simple operation. In addition, the probe has good reusability and a wide range of applications. The linear range for copper ions was 0.005–100 μM with a limit of detection of 5 nM. Moreover, the experiments also showed that the probe was a reliable and specific probe for copper ion imaging in living cells.