贵金属纳米结构为敏感层的锥形光纤探针及其SERS活性

Noble Metal Nanostructures Assembled Tapered Fiber Probes and Their SERS Performance

表面等离激元纳米结构与便携式光纤拉曼系统相结合,在液体样品和生物活体组织的快速、实时监测上有较好的应用前景。其核心技术是将具有表面增强拉曼散射(SERS)活性的贵金属纳米结构耦合到光纤探针表面。本文基于共价键结合原理,将3-巯丙基三甲氧基硅烷通过与锥形光纤探针表面的硅羟基形成共价键修饰在光纤上;同时,硅烷偶联剂末端的巯基与金或银纳米结构形成Au-S或Ag-S共价键,将金纳米粒子和银纳米立方体牢牢吸附到光纤探针表面。这种SERS光纤探针具有很高的稳定性(SERS信号相对标准偏差低于3%),对农残甲基对硫磷的敏感度达到10纳摩尔,对污染物的远程、便携式在线检测具有重要意义。

The integration of plasmonic nanostructures with portable fiber Raman spectrometer shows great po- tential in real time detection of remote liquid samples and in-vivo species. In this system, the surface enhanced Raman scattering （SERS） active noble metal nanostructures are required to bind on the fiber surface to generate stable SERS signals toward the target species. Herein we show that by using thiol-terminated silane couple agent （3-mercaptopropyl trimethoxysilane） which can be decorated on the silica surface of fiber probe, SERS-active Au nanospheres and Ag nanocubes can be stably assembled on the fiber surface through the readily formed Au-S and Ag-S covalent bond. The resultant SERS fiber probes demonstrate high signal reproducibility （relative standard deviation lower than 3%） and can be sensitive to 10^-8 M methyl parathion, showing poten- tials in SERS-based online and portable detection of liquid samples.