Off-on fluorescence monitoring of intracellular Ag(+) in single living cells using an Ag(+)-responsive probe.

Detection of silver ions (Ag(+)) in living cells has becoming more and more attractive due to the important biological impact of Ag(+) on cellular functions. Here, we put forward a new approach to realize the in situ fluorescence imaging and detection of Ag(+) in single cells via an ultrasensitive Ag(+)-responsive probe, 3',6'-bis (diethylamino)-2-(2-iodoethyl) spiro[isoindoline-1,9'-xanthen]-3-one (BDISIX). In the presence of Ag(+), the fluorescence of the probe can be turned 'on', generating strong red fluorescence. Using breast cancer cells (MCF-7) as the example, we successfully realize the imaging of intracellular Ag(+) through one-step incubation of the probe, which is especially convenient and fast for the in situ intact detection of Ag(+) in living cells.