A fluorescein derivative-based fluorescent sensor for selective recognition of copper(II) ions

A novel fluorescein-based sensor FR-L was designed and synthesized with good yield for recognizing copper(II) ions in living cells. The sensor, incorporating 5-aminoisophthalic acid methyl ester with fluorescein, was synthesized and fully characterized by crystal test, (HNMR)-H-1, and ESI-MS analyses. The sensor showed a quenching response with the addition of copper(ll) ions which was ascribed to the cooperation between the sensor and copper(II) ions. Meanwhile, the sensor exhibited high selectivity over other metal ions and displayed more obvious changes of absorption. Finally, fluorescent imaging in living cells indicated the capability of detecting copper(II) ions in biological system. (C) 2017 Published by Elsevier B.V.