半胱氨酸修饰金纳米棒光学性质的研究

Research on the Optical Properties of Cysteine Modified Gold Nanorods

采用种子生长法制备了不同长径比的金纳米棒,并通过金硫键的结合在其表面包覆半胱氨酸分子。利用紫外-可见吸收光谱仪,扫描电子显微镜以及拉曼光谱仪等对样品进行分析和表征。实验结果表明金纳米棒产率较高,且一致性较好。表面修饰后的金纳米棒的纵向吸收峰发生蓝移,表明半胱氨酸分子与金纳米棒的结合有助于溶液分散性的提升。以结晶紫为探针分子,随着金纳米棒长径比的增加其拉曼增强效果变强。进一步分析发现,修饰后的金纳米棒的表面增强拉曼光谱的增强效果并未受到影响。通过金纳米棒与半胱氨酸分子牢固的结合,一方面可以提高金纳米棒溶液的分散性与稳定性;另一方面半胱氨酸分子可为金纳米棒修饰其它有机官能团提供了一个牢固的桥梁,有效地拓展了金纳米棒的应用方向。

Employing the seed mediated method, we have synthesized gold nanorods with different aspect ratios. With cysteine coated on the surface of the gold nanorods, the optical properties were investigated with the help of UV-Vis absorption spectroscopy, scanning electron microscopy and Raman spectroscopy. Experimental results indicate that the size and shape of the gold nanorods yield a high consistency. Moreover, with the modified surface of the gold nanorods, the dispersity can be greatly improved. With CV as a probe molecule, the enhanced Raman intensity can be ob- tained with a larger aspect ratio of the gold nanorods. And the coated cysteine does not affect the Raman properties of the gold nanorods. Thus, with the coated cysteine molecules, the gold nanoro- ds not only have a unique optical properties and an excellent SERS-activity, but also it can widely be used with a free affinity function.