Sensors Based On Fluorescent Gold Nanoclusters

Gold nanoclusters are a type of novel nanomaterials, with ultral-small size(<2nm)comparable to the Fermi wavelength of electrons, they can provide molecule-like properties including discrete electronic states and size-dependent fluorescence.Fluorescent metal nanoclusters have an attractive set of features, such as high luminescence intensity, excellent stability and good biocompatibility, making them ideal fluorescent probe to detect target substances. Most of the detections are based on either the enhancement or the quenching of the fluorescence. In this paper, we established a series of sensing systems based on the fluorescence quenching effect from targets.In the first part of this work, we synthesized gold nanoclusters stabilized by bovine serum ablbumin, and studied the response of gold nanoclusters fluorescent probe toward iodate. Furthermore it was found that extra iodide ion could enhance this process, and even a small amount of iodate could lead to significant quenching. Therefore, we developed a high sensitive iodate sensor.In the second part, we established a method for detecting oxidative species(such as,nitrite and bromate) indirectly with the interaction with fluorescent gold nanoclusters.With the pre-reaction between the target ions and extra iodide, iodine was generated,which could induce the fluorescence quenching of fluorescence gold nanoclusters. No volumetric titrations were required during this process and this methodology could be extended for the measurement of a wider range of range of targets.