Li Baoshun, Li Jianjun, Zhao Junwu
The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China.
The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2015 Jan 5;134:40-7. doi: 10.1016/j.saa.2014.06.075. Epub 2014 Jun 21.
Noble metal (e.g., gold and silver) nanomaterials possess unique physical and chemical properties. In present work, silver nanoclusters (also known as silver quantum clusters or silver quantum dots) were synthesized by bovine serum albumin (BSA) biomineralization. The synthesized silver nanoclusters were characterized by UV-VIS absorption spectroscopy, fluorescence spectroscopy, upconversion emission spectroscopy, TEM, HRTEM and FTIR spectroscopy. TEM results showed that the average size of the silver nanoclusters was 2.23 nm. Fluorescence results showed that these silver nanoclusters could emit weak near-infrared (NIR) fluorescence (the central emission wavelength being about 765 nm). And the central excitation wavelength was about 395 nm, in the UV spectral region. These silver nanoclusters showed an extraordinarily large gap (about 370 nm) between the central excitation wavelength and central emission wavelength. In addition, it was found that these silver nanoclusters possess upconversion emission property. Upconversion emission results showed that the upconversion emission spectrum of the silver nanoclusters agreed well with their normal fluorescence emission spectrum. The synthesized silver nanoclusters showed high stability in aqueous solution and it was considered that they might be confined in BSA molecules. It was found that silver nanoclusters might enhance and broaden the absorption of proteins, and the protein absorption peak showed an obvious red shift (being 7 nm) after the formation of silver nanoclusters.
贵金属（如金和银）纳米材料具有独特的物理和化学性质。在本工作中，通过牛血清白蛋白（BSA）生物矿化合成了银纳米簇（也称为银量子簇或银量子点）。采用紫外可见吸收光谱、荧光光谱、上转换发射光谱、透射电子显微镜（TEM）、高分辨透射电子显微镜（HRTEM）和傅里叶变换红外光谱（FTIR）对合成的银纳米簇进行了表征。TEM结果表明，银纳米簇的平均尺寸为2.23 nm。荧光结果表明，这些银纳米簇能发射微弱的近红外（NIR）荧光（中心发射波长约为765 nm）。中心激发波长约为395 nm，处于紫外光谱区域。这些银纳米簇在中心激发波长和中心发射波长之间显示出非常大的差距（约370 nm）。此外，发现这些银纳米簇具有上转换发射特性。上转换发射结果表明，银纳米簇的上转换发射光谱与其正常荧光发射光谱吻合良好。合成的银纳米簇在水溶液中表现出高稳定性，并且认为它们可能被限制在BSA分子中。发现银纳米簇可能增强并拓宽蛋白质的吸收，并且在银纳米簇形成后蛋白质吸收峰出现明显的红移（为7 nm）。
