Shao Yunpeng, Li Sha, Niu Yue, Wang Zezhou, Zhang Kai, Mei Linyu, Hao Yaowu
School of Mechanical Engineering, North University of China, Taiyuan 030051, China.
Department of Materials Science and Engineering, University of Texas at Arlington, Arlington, TX 76019, USA.
Nanomaterials (Basel). 2022 Jun 10;12(12):2002. doi: 10.3390/nano12122002.
The development of a facile surface-enhanced Raman scattering (SERS) sensor for the on-site detection of trace molecules in liquid phase is a compelling need. In this paper, a three-dimensional (3D) dendritic Au-Ag nanostructure was constructed by a two-step electro displacement reaction in a capillary tube for the on-site liquid phase detection of trace molecules. The multiplasmon resonance mechanism of the dendritic Au-Ag structure was simulated using the finite-difference time domain (FDTD) method. It was confirmed that the highly branched 3D structure promoted the formation of high-density "hot spots" and interacted with the gold nanoparticles at the dendrite tip, gap, and surface to maximize the spatial electric field, which allowed for high signal intensification to be observed. More importantly, the unique structure of the capillary made it possible to achieve the on-site detection of trace molecules in liquids. Using Rhodamine 6G (R6G) solution as a model molecule, the 3D dendritic Au-Ag substrate exhibited a high detection sensitivity (10 mol/L). Furthermore, the developed sensor was applied to the detection of antibacterial agents, ciprofloxacin (CIP), with clear Raman characteristic peaks observed even at concentrations as low as 10 mol/L. The results demonstrated that the 3D dendritic Au-Ag sensor could successfully realize the rapid on-site SERS detection of trace molecules in liquids, providing a promising platform for ultrasensitive and on-site liquid sample analysis.
开发一种用于现场检测液相中痕量分子的简便表面增强拉曼散射（SERS）传感器迫在眉睫。本文通过毛细管中的两步电置换反应构建了一种三维（3D）树枝状金-银纳米结构，用于现场液相检测痕量分子。利用时域有限差分（FDTD）方法模拟了树枝状金-银结构的多等离子体共振机制。证实了高度分支的三维结构促进了高密度“热点”的形成，并与枝晶尖端、间隙和表面的金纳米颗粒相互作用，使空间电场最大化，从而能够观察到高信号增强。更重要的是，毛细管的独特结构使得实现液体中痕量分子的现场检测成为可能。以罗丹明6G（R6G）溶液作为模型分子，3D树枝状金-银基底表现出高检测灵敏度（10 mol/L）。此外，所开发的传感器应用于抗菌剂环丙沙星（CIP）的检测，即使在低至10 mol/L的浓度下也观察到清晰的拉曼特征峰。结果表明，3D树枝状金-银传感器能够成功实现液体中痕量分子的快速现场SERS检测，为超灵敏和现场液体样品分析提供了一个有前景的平台。
