A reversible biocompatible "turn-on" fluorescent probe for the detection of mercury(II)

A new rhodamine-based fluorescent probe based on the known ring-opening mechanism of rhodamine derivative, was successfully synthesized and demonstrated to detect the Hg²⁺ with high selectivity and sensitivity in aqueous solution and living cells. In the presence of Hg²⁺, the probe exhibit remarkably amplified absorption with a binding constant determined as 8.76±0.13, followed by a distinct change in color and 560-fold enhancement of fluorescence with a reversible response and little interference with other biological relevant metal ions. Moreover, the confocal microscopic switch-on imaging in MCF-7 cells of the probe towards Hg²⁺, together with its non-cytotoxicity and efficient cellular uptake, confirmed that the probe can be used as a biocompatible probe for monitoring of Hg²⁺ in living cells.