DST Unit of Nanoscience, Department of Chemistry, Indian Institute of Technology Madras, Chennai-600 036, India.
Nanoscale. 2012 Jul 21;4(14):4255-62. doi: 10.1039/c2nr30729d. Epub 2012 Jun 8.
We report the synthesis of luminescent AuAg alloy quantum clusters (QCs) in bovine serum albumin (BSA), for the first time, with experimentally determined atomic composition. Mixing of the as-synthesized protein-protected Au and Ag clusters resulted in the formation of alloy AuAg clusters within the BSA. Mass spectrometric analysis of the product of a 1 : 1 molar ratio reaction mixture of Au(QC)@BSA and Ag(QC)@BSA suggested that the alloy clusters could be Au(38-x)Ag(x)@BSA. Further analyses by standard techniques revealed that the alloy cluster core of ∼1.2 nm diameter is composed of nearly zero valent Au and Ag atoms that exhibit distinctly different steady state and time resolved excited state luminescence profiles compared to the parent clusters. Tuning of the alloy composition was achieved by varying the molar ratio of the parent species in the reaction mixture and compositional changes were observed by mass spectrometry. In another approach, mixing of Au(3+) ions with the as-synthesized Ag(QC)@BSA also resulted in the formation of alloy clusters through galvanic exchange reactions. We believe that alloy clusters with the combined properties of the constituents in versatile protein templates would have potential applications in the future. The work presents interesting aspects of the reactivity of the protein-protected clusters.
我们首次报告了在牛血清白蛋白（BSA）中合成具有实验确定原子组成的发光 AuAg 合金量子点（QC）。混合合成的蛋白质保护的 Au 和 Ag 簇会导致在 BSA 内形成合金 AuAg 簇。对 Au(QC)@BSA 和 Ag(QC)@BSA 的 1:1 摩尔比反应混合物的产物进行质谱分析表明，合金簇可能是 Au(38-x)Ag(x)@BSA。通过标准技术进一步分析表明，直径约为 1.2nm 的合金簇核由近乎零价的 Au 和 Ag 原子组成，与母体簇相比，其稳态和时间分辨激发态发光谱明显不同。通过改变反应混合物中母体物质的摩尔比可以实现合金组成的调谐，并通过质谱观察到组成变化。在另一种方法中，将 Au(3+) 离子与合成的 Ag(QC)@BSA 混合也通过电置换反应形成合金簇。我们相信，具有多功能蛋白质模板中成分的组合特性的合金簇将在未来具有潜在的应用。这项工作展示了蛋白质保护的簇的反应性的有趣方面。
