Preparation Of Gold Nanoclusters And Their Applications In The Detection Of Metal Ions

Noble metal nanoclusters have unique optical properties with high fluorescene, low toxicity, high solubility, strong stability and good biocompatibility, making them to have abroad potential applications in sample analysis and biomedical imaging. Therefore, in recent years, they have attracted lots attentions. Here, we prepared water-soluble gold nanoclusters and used them as fluorescence probes. These probes have realized the detection of metal ions quickly and easily. The main research contents are summarized as following:1. We prepared gold nanoclusters with bovine serum albumin（BSA）, human serum albumin（HSA）, cysteine（Cys） and glutataione（GSH） as the weak reducers and protecting reagents. We also studied the properties of Au NCs, including the size, the light stability, the acid and the alkali resistance, the quantum yield and cell toxicity.2. A label-free optical probe was developed for Ca²⁺ detection based on the aggregation-induced emission property（AIE） of Cys-Au NCs complexes. Upon incubation with Ca²⁺, the Cys-Au NCs complexes rapidly aggregated through Cys-Ca²⁺ interaction, resulting in a considerably luminescent emission. The label-free probe was low-cost, simple in design and fast in response.3. The GSH-Au NCs were then employed as visual probes for the detection of Pb²⁺ based on the aggregation-induced emission enhancement property of Au NCs. When the glutathione capped Au NCs probes were encountered to Pb²⁺, they rapidly formed aggregates through GSH-Pb²⁺ interaction in 1 minute, resulting in an enhanced luminescence intensity. The enhanced luminescence intensities showed a linear dependence on the concentrations of Pb²⁺ with a satisfactory selectivity towards 12 kinds of divalent metal ions. More importantly, the probe could also be used for on-site testing to inspect Pb²⁺ contamination by using a portable UV flashlight.