Fluorescence Detection Based On Gold Nanoclusters

Noble metal nanoclusters are ultra-small fluorescent nanomaterials with unique physicochemical properties,such as excellent optical stability,water solubility and biocompatibility.The preparation and application of metal nanoclusters are simple,with stable fluorescence and adjustable fluorescence wavelength.Therefore,many researchers pay attention to them and they are applied in environmental analysis and biosensors.In this paper,two different kinds of fluorescent gold nanoclusters were synthesized,and fluorescent probes for molybdenum and blood homocysteine were constructed by using the idea of indirect fluorescence detection.It was found that molybdenum was an effective catalyst for hydrogen peroxide oxidation of iodide ion to produce iodine elemental,and the resulting iodine elemental could significantly quench the gold nanocluster.Therefore,by combining it with the fluorescent gold nanocluster,the detection limit as low as nanomolar level(0.2 nM)could be obtained,which was similar to the detection limit of ICP-OES technology.Because of the low requirements of the instrument,this method is very practical when these expensive and complex methods cannot be used.Due to its excellent detection performance,interference can be reduced by large dilution to detect molybdenum content in plant samples.The method can be applied to a variety of target objects,such as other minerals or food samples.The detection of blood homocysteine is an important index to diagnose coronary heart disease and cerebrovascular disease.It was found that copper ions could quench the fluorescence of glutathione(GSH)gold nanoclusters,and the fluorescence recovered after chelating with copper ions when Homocysteine(Hcy)was added.There was no fluorescence recovery when cysteine(cys)with similar structure was added to the system.In the fourth section of this paper,a fluorescent probe based on GSH gold nanocluster was introduced to detect and distinguish homocysteine and cysteine simultaneously,and the selectivity of the probe to these mercaptan was studied.The detection method can be sensitive and simple to distinguish Hcy and cys,which is expected to play a role in practical detection.