HKUST-Shenzhen Research Institute; Department of Chemistry, The Hong Kong University of Science and Technology.
HKUST-Shenzhen Research Institute; Department of Chemistry, The Hong Kong University of Science and Technology;
J Vis Exp. 2022 Jun 23(184). doi: 10.3791/63862.
Surface-enhanced Raman spectroscopy (SERS) enables the ultrasensitive detection of analyte molecules in various applications due to the enhanced electric field of metallic nanostructures. Salt-induced silver nanoparticle aggregation is the most popular method for generating SERS-active substrates; however, it is limited by poor reproducibility, stability, and biocompatibility. The present protocol integrates optical manipulation and SERS detection to develop an efficient analytical platform to address this. A 1064 nm trapping laser and a 532 nm Raman probe laser are combined in a microscope to assemble silver nanoparticles, which generate plasmonic hotspots for in situ SERS measurements in aqueous environments. Without aggregating agents, this dynamic plasmonic silver nanoparticle assembly enables an approximately 50-fold enhancement of the analyte molecule signal. Moreover, it provides spatial and temporal control to form the SERS-active assembly in as low as 0.05 nM analyte-coated silver nanoparticle solution, which minimizes the potential perturbation for in vivo analysis. Hence, this optical trapping-integrated SERS platform holds great potential for efficient, reproducible, and stable molecular analyses in liquids, especially in aqueous physiological environments.
表面增强拉曼光谱（SERS）由于金属纳米结构的增强电场，能够在各种应用中实现对分析物分子的超灵敏检测。盐诱导的银纳米颗粒聚集是产生 SERS 活性衬底的最常用方法；然而，它受到重现性差、稳定性和生物相容性差的限制。本方案通过光操纵和 SERS 检测相结合，开发了一种有效的分析平台来解决这个问题。在显微镜中组合使用 1064nm 捕获激光和 532nm 拉曼探针激光，组装银纳米颗粒，在水相环境中产生等离子体热点，用于原位 SERS 测量。在没有聚集剂的情况下，这种动态等离子体银纳米颗粒组装可将分析物分子信号增强约 50 倍。此外，它提供了空间和时间控制，以在低至 0.05nM 分析物包被的银纳米颗粒溶液中形成 SERS 活性组装，从而最小化对体内分析的潜在干扰。因此，这种光捕获集成 SERS 平台在液体中进行高效、可重复和稳定的分子分析方面具有很大的潜力，特别是在水相生理环境中。
