College of Optical and Electronic Technology, China Jiliang University, 310018 Hangzhou, China.
College of Optical and Electronic Technology, China Jiliang University, 310018 Hangzhou, China; Key Laboratory of Urban Agriculture in Central China, College of Horticulture & Forestry Sciences, Huazhong Agricultural University, 430070 Wuhan, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2021 Jul 5;255:119717. doi: 10.1016/j.saa.2021.119717. Epub 2021 Mar 23.
The silver nanoparticles have been frequently used in SERS detection, for their unique optical properties and sensitive surface Raman enhancement properties. However, as the preparation of silver nanoparticles will use polyvinylpyrrolidone (PVP) to achieve the effect of reducing agent and surfactant, the surface of the prepared silver nanoparticles will be wrapped by PVP, forming an insulating layer and an ill-defined AgNPs interface, which limits the plasmonic coupling between the laminates of AgNPs. This paper reported a simple method to remove PVP for high performance and reusable SERS substrate, and the residue of PVP was studied after clean centrifugal by ethanol or water. When the number of cleaning times reached 10, there was basically no residual of PVP. The cleaned AgNPs interface effectively enhanced the plasma resonance of the local surface (LSPR) and greatly improved the SERS activity of the substrate. Moreover, probe molecules (R6G) are introduced to study the influence of single molecule PVP on subsequent detection. Through the competitive relationship between the two, it can be concluded that residual PVP has basically no influence on detection of the molecular which absorbed stronger than PVP, and the remaining PVP can be ignored.
银纳米粒子由于其独特的光学性质和灵敏的表面拉曼增强性质，经常被用于 SERS 检测。然而，由于银纳米粒子的制备会使用聚乙烯吡咯烷酮（PVP）来实现还原剂和表面活性剂的效果，因此制备的银纳米粒子表面会被 PVP 包裹，形成绝缘层和不明确的 AgNPs 界面，这限制了 AgNPs 层之间的等离子体耦合。本文报道了一种简单的去除 PVP 的方法，以获得高性能和可重复使用的 SERS 基底，并用乙醇或水进行离心清洗以去除残留的 PVP。当清洗次数达到 10 次时，基本上没有 PVP 残留。清洁后的 AgNPs 界面有效地增强了局域表面等离子体共振（LSPR），并极大地提高了基底的 SERS 活性。此外，引入探针分子（R6G）来研究单分子 PVP 对后续检测的影响。通过两者之间的竞争关系，可以得出结论，残留的 PVP 对吸附强度强于 PVP 的分子的检测基本没有影响，可以忽略剩余的 PVP。
