Formation of Fluorescent Metal (Au, Ag) Nanoclusters Capped in Bovine Serum Albumin Followed by Fluorescence and Spectroscopy
Formation of Fluorescent Metal (Au, Ag) Nanoclusters Capped in Bovine Serum Albumin Followed by Fluorescence and Spectroscopy
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DOI：
10.1021/jp111820b
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发表时间：
2011-06-09
影响因子：
3.7
通讯作者：
Schneider, Marc
中科院分区：
文献类型：
--
作者：
Le Guevel, Xavier;Hoetzer, Benjamin;Schneider, Marc
采用湿化学法将荧光贵金属（Au，Ag）纳米团簇标记到牛血清白蛋白（BSA）上。光谱和荧光研究涉及的pH值和还原剂的性质的作用的大小和金属簇的氧化态。在pH 8下制备的发蓝光（λ = 450 nm）的小金纳米团簇（8个原子）与BSA弱键合，在较高pH下生长以形成发红光（λ = 690 nm）的较大团簇（25个原子），其经由硫基团与BSA共价键合。X射线光电子能谱（XPS）测量表明，Au（I）的存在下，只有大的集群。在强还原剂的存在下合成了标记到蛋白质上的小银纳米团簇，其在红色区域中具有荧光发射，并且仅存在Ag（0）。稳态和寿命测量证实了Au（I）的大小和氧化态对蛋白质内金属核心的稳定性和对长寿命组分（τ> 170 ns）的存在的关键影响。
Fluorescent noble metal (Au, Ag) nanoclusters have been biolabeled to bovine serum albumin (BSA) by wet chemistry. Spectroscopic and fluorescence investigations relate the role of the pH and the nature of the reducing agent to the size and the oxidation state of metal clusters. Blue-emitting (lambda = 450 nm) small gold nanoclusters (eight atoms) prepared at pH 8 weakly bonded to BSA grow at higher pH to form red-emitting (lambda = 690 nm) bigger clusters (25 atoms) covalently bonded to BSA via the sulfur group. X-ray photoelectron spectroscopy (XPS) measurements indicate the presence of Au(I) only for the big clusters. Small silver nanoclusters labeled to the protein with a fluorescence emission in the red region are synthesized in the presence of a strong reducing agent and present only Ag(0). Steady-state and lifetime measurements confirm the crucial impact of the size and the oxidation state of Au(I) on the stabilization of the metal core inside the protein and on the presence of a long lifetime component (tau > 170 ns).