State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering, Southeast University , Nanjing 210096, P. R. China.
ACS Appl Mater Interfaces. 2014 Mar 12;6(5):3331-40. doi: 10.1021/am405357v. Epub 2014 Feb 26.
Recent studies have conclusively shown that the plasmonic performance of Au nanostructures can be enhanced by incorporating Ag. Here, we developed a simple and robust approach for preparing core-shell Au-Ag nanoshuttles (NSs) using single-crystal Au nanorods (NRs) as cores. Upon tailoring the temperature of the reaction system containing alkaline glycine buffer (pH 8.5), exceptionally monodisperse Au-Ag NSs with sharp tips and tunable shell thickness could be routinely achieved in high yield through an epitaxial growth process. In particular, high-resolution transmission electron microscopy and nitric acid corrosive experiments revealed that the shells of these NSs consisted of a homogeneous Au-Ag alloy, rather than pure Ag or Au as previously reported. It was found that glycine played an important role in determining the final metal contents of the shell by regulating the reduction kinetics. In addition, the obatined Au-Ag NSs with sharp tips were shown to have significantly improved refractive index sensitivity and surface-enhanced Raman scattering activity relative to the original Au NRs, making these materials promising for biomedical applications, such as biosensing and biolabeling.
最近的研究已经明确表明，通过掺入 Ag，Au 纳米结构的等离子体性能可以得到增强。在这里，我们开发了一种简单而强大的方法，使用单晶 Au 纳米棒 (NRs) 作为核来制备核壳 Au-Ag 纳米梭 (NSs)。通过调整含有碱性甘氨酸缓冲液 (pH 8.5) 的反应体系的温度，可以通过外延生长过程以高产率常规地获得具有尖锐尖端和可调壳厚度的异常单分散 Au-Ag NSs。特别是，高分辨率透射电子显微镜和硝酸腐蚀性实验表明，这些 NSs 的壳由均匀的 Au-Ag 合金组成，而不是以前报道的纯 Ag 或 Au。研究发现，甘氨酸通过调节还原动力学在确定壳的最终金属含量方面起着重要作用。此外，与原始 Au NRs 相比，具有尖锐尖端的所得 Au-Ag NSs 表现出显著提高的折射率灵敏度和表面增强拉曼散射活性，这使得这些材料在生物医学应用中具有广阔的前景，如生物传感和生物标记。
