Visualizing Hg2+ ions in living cells using a FRET-based fluorescent sensor

A novel FRET fluorescent sensor for Hg2+ imaging in living cells is rationally designed based on a coumarin-rhodamine platform. RBC1 exhibit high selectivity and excellent sensitivity in both absorbance and fluorescence detection of Hg2+ in aqueous solution. After addition of increasing concentrations of Hg2+, it result in the decrease of coumarin emission at 467 nm and a new emission profile of rhodamine at 590 nm gradually increased. The response time to Hg2+ is less than 2 min, and other metal ions including Fe2+, Mn2+, Ni2+, Co2+, Cu2+, Zn2+, Cd2+, Pb2+, and Cr3+ had no interference. In addition, fluorescent imaging of Hg2+ in A375 cells is also successfully demonstrated. The design strategy of two fluorophores switching in this work would help to extend the development of FRET fluorescent sensors. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.