Synthesis And Application Of Gold Nanoclusters

With fast development of economy, the requirements of living environment are aslo increased, particularly heavy metal ions pose a threat to human health. Fluorescent metal nanoclusters display advantages of quantum measurement, outstanding cell membrane permeability, excellent water solubility and biocompatibility characteristics, which were preferred to cell imaging, biological sensors and biological markers. In recent years, fluorescent gold nanoclusters have been applied to detection of metal ions. In this paper, we synthesize three kinds of fluorescent gold nanoclusters and study the application of metal ions detection. The main contents are as follows: 1. The fluorescent gold nanoclusters（Au NCs@GSH） which were modified by glutathione（GSH） were gained through the method of phase transfer at room temperature. The prepaired Au nanoclusters exhibited homogeneous dispersion with the average size of 2 nm, and had high selectivity to copper ions with the low limit of 0.88 nM in the linear range of 2.00-3.00×103 nM. The result revealed that Au NCs@GSH could be applied to analysis of copper ions in drinking water. 2. The fluorescent gold nanoclusters（Au NCs@HSA） modified with human serum albumin were produced by microwave-assisted method. Au NCs@HSA had good fluorescence response to mercury ions. The detection limit was evaluated and found to be 0.93 nM. The linear correlation was over the range from 24.42-1.60×103 nM, which indicated Au NCs@HSA could be used to detect mercury ions as biosensor. In addition, the gold nanoclusters also were used in the field of cell imaging as high quality fluorescence probes due to the lower biological toxicity. 3. According to different fluorescence emission of nanoclusters, the composite gold nanoclusters（Au NCs） were prepared, which can lead to fluorescence response in presence of Pb²⁺ and Cu²⁺at the same time. Au NCs had double emissions at 512 nm and 612 nm and displayed yellow-green light under UV light irradiation of 365 nm wavelength. When copper ions were detected, the green light appeared company with the disappearing of red light. And the opposite phenomenon was arised with the addition of lead ions. The sensitive fluorescence response to the same metal ion was almost no change before and after compositing with the nanoclusters. And the composite gold nanoclusters exhibited excellent correlation in the range of 1.00-1.20×104 nM. Furthermore, the composite material could be applied in the detection of the actual sample.