An Aggregation-Induced Phosphorescence-Active "Turn-Off" Nanosensor Based on Ferric-Specific Quenching of Luminescent and Water-Soluble Au(I)-Cysteine Nanocomplexes.

Recently, aggregation-induced emission (AIE) has attracted extensive attention. Herein we report an AIP-active "turn-off" nanosensor based on ferric-specific quenching of photoluminescence (PL) of water-soluble Au(I)-cysteine nanocomplexes. The Au(I)-cysteine nanocomplexes were AIP-active, showing a PL peak at 590 nm. Transmission electron microscopy (TEM) characterization revealed that they show the characteristic morphology of nanofibers. High-speed centrifugation characterization and zeta potential measurement indicated that they are highly water-soluble. Interestingly, their PL could be quenched specifically by ferric ions over the other common 18 metal ions. Further TEM characterizations revealed that the quenching process was accompanied by the ferric-specific dissociation of Au(I)-cysteine nanofibers. These observations have enabled the development of a water-soluble AIP-active "turn-off" nanosensor based on Au(I) nanocomplexes for selective and sensitive detection of ferric ions. This study indicates that specific quenching and disassociation of AIP-active nanocomplexes might be a promising route for development of novel luminescent nanosensors.