Wark Alastair W, Stokes Robert J, Darby Steven B, Smith W Ewen, Graham Duncan
Centre for Molecular Nanometrology, WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, U.K., G1 1XL.
J Phys Chem C Nanomater Interfaces. 2010 Oct 28;114(42):18115-18120. doi: 10.1021/jp107559x. Epub 2010 Oct 5.
A novel wide-field approach for the real-time Surface Enhanced Raman Scattering (SERS) imaging of multiple silver nanoparticle clusters suspended in solution is described. This method enables direct correlation of the SERS activity of a single nanoparticle aggregate and its size through measurement of the cluster diffusion coefficient and can also be performed in a high-throughput basis. As a first demonstration, we investigate the salt-induced aggregation of silver nanoparticles in the presence of a reporter tag molecule, which has a high affinity for the nanoparticle surface. In addition to tracking individual particles, direct comparison of Rayleigh and SERS videos of the same colloid solution enabled measurement of the fraction of individual clusters that are SERS active and the dependence of this value on the relative concentration of the tag molecule. Furthermore, given the ability to also rapidly profile any nonuniformity in particle size distributions, we expect this approach will not only provide a new tool for the fundamental understanding of SERS but also significantly contribute to the development of an array of emerging nanoparticle-enhanced biomolecule and imaging detection platforms.
本文描述了一种新颖的宽场方法，用于对溶液中悬浮的多个银纳米颗粒簇进行实时表面增强拉曼散射（SERS）成像。该方法通过测量簇扩散系数，能够直接关联单个纳米颗粒聚集体的SERS活性与其尺寸，并且还可以高通量方式进行。作为首次演示，我们研究了在存在对纳米颗粒表面具有高亲和力的报告标签分子的情况下，盐诱导的银纳米颗粒聚集。除了跟踪单个颗粒外，对同一胶体溶液的瑞利和SERS视频进行直接比较，能够测量具有SERS活性的单个簇的比例以及该值对标签分子相对浓度的依赖性。此外，鉴于能够快速描绘颗粒尺寸分布中的任何不均匀性，我们预计这种方法不仅将为深入理解SERS提供一种新工具，还将为一系列新兴的纳米颗粒增强生物分子和成像检测平台的开发做出重大贡献。
