Synthesis Of Gold And Copper Nanoclusters For Biological And Chemical Analysis

In recent years, metal nanoclusters（MNCs） have attracted more and more attentions due to their attractive features such as quantum size effect, good biocompatibility, high sensitivity, photostability and larger Stokes shift. Owing to these excellent properties, we attempt to develop new templates and optimized conditions for preparing gold and copper nanoclusters and explore their applications in analysis. The main contains are listed as follows:1. A novel one-pot strategy for synthesizing fluorescent gold nanoclusters（AuNCs） has been well established while tyrosine（Tyr） played a role as stabilizer. Subsequently, the shape, fluorescence property and stability of the obtained tyrosine gold nanoclusters（AuNCs@Tyr） were elucidated by UV-vis absorption, fluorescence spectroscopy and high resolution transmission electron microscopy（HR-TEM）. The as-prepared AuNCs@Tyr exhibited a fluorescence emission at 470 nm and emitted obvious yellowgreen fluorescence under UV light（365 nm）. The AuNCs@Tyr existed within the size range of 1-3 nm with a homogeneous size. In addition, the AuNCs@Tyr described here was applied for detections of tyrosinase（TR） activity, which was based on the mechanism of aggragations of AuNCs@Tyr occuring on the active sites of TR once TR was introduced, thus leading to the fluorescence quenching of AuNCs@Tyr. Accordingly, TR was analyzed in a linear range of 0.5-200 u mL-1 with a detection limit of 0.08 u mL-1 at a signal-to-noise ratio of 3. Significantly, the practicability of this sensing method was further validated by assaying TR in human serum samples, confirming its potential for broadening roads of detecting TR activity.2. Glutathione（GSH）, playing roles as both a reducing reagent and protecting ligand, has been successfully employed for synthesizing water-soluble Cu nanoclusters（CuNCs@GSH） on the basis of a simple and facile approach. The as-prepared CuNCs exhibited a fluorescence emission at 600 nm and emitted obvious red fluorescence under UV light（365 nm）. Subsequently, the CuNCs described here was employed as a broad-range pH sensor by virtue of the fluorescence intensity of CuNCs responding sensitively to pH fluctuating in a linear range of 4.0-12.0. Meanwhile, these prepared CuNCs were applied for detections of vitamin B₁（VB₁） on the basis of positively charged VB₁ neutralizing the negative surface charge of CuNCs, thus leading to the instability and aggregations of CuNCs, and further facilitating to quench their fluorescence. In addition, the proposed analytical method permitted detecting VB₁ with a linear range of 2.0×10-8-1.0×10-4 mol L-1 as well as a detection limit of 4.6×10-9 mol L-1. Eventually, the practicability of this sensing approach was validated by assaying VB₁ in human urine samples and pharmaceutical tablets, confirming its potential to broaden avenues for assaying VB₁ in actual samples.In summary, we suppose that the research results describes above would be beneficial for us to understand deeply their characters of metal nanoclusters, and enlarge their applications in biological and chemical analysis.