Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, School of Mechanical Engineering , Southeast University , Nanjing 211189 , China.
Langmuir. 2019 Dec 3;35(48):15795-15804. doi: 10.1021/acs.langmuir.9b00970. Epub 2019 Jun 27.
An evaporative self-assembly strategy for constructing a long-life 3D surface-enhanced Raman scattering (SERS) hot spot matrix is proposed with the assistance of glycerol to improve the spectral sensitivity and reproducibility. Different from the traditional wetting-state or drying-state methods, silver nanoparticles (AgNPs) in the glycerol-stabilized 3D SERS hot spot matrix can be maintained in the translation state for more than 7 days with the maximal uniformity of the interparticle distance. Brownian dynamics simulations reveal that more hot spots emerge in the glycerol-stabilized AgNPs matrix, and the distances between the AgNPs are not fixed but balanced in a small range by the interplay of the van der Waals attraction and the electrostatic repulsion. A 2 orders of magnitude extra SERS enhancement, more stable peak frequencies, and a narrower peak full width at half-maximum (fwhm) can therefore be obtained, which ensure extremely stable and reproducible SERS signals. Single-molecule detection sensitivity utilizing the glycerol-stabilized 3D SERS hot spot matrix has been demonstrated by collecting the SERS spectra of dye molecules at a concentration of as low as 0.5 aM (5 × 10 M) with a good signal-to-noise ratio. A long lifetime, ultrahigh SERS enhancement, and extremely stable peak shape make the 3D SERS hot spot matrix a sensitive, practical, and reliable tool for the detection and analysis of analytes at ultralow concentration or even at the single-molecule level in complex matrixes.
提出了一种利用甘油辅助构建长寿命 3D 表面增强拉曼散射（SERS）热点矩阵的蒸发自组装策略，以提高光谱灵敏度和重现性。与传统的润湿态或干燥态方法不同，甘油稳定的 3D SERS 热点矩阵中的银纳米粒子（AgNPs）可以在平移状态下保持超过 7 天，颗粒间距离的最大均匀性。布朗动力学模拟表明，甘油稳定的 AgNPs 基质中出现了更多的热点，AgNPs 之间的距离不是固定的，而是通过范德华吸引力和静电排斥力的相互作用在小范围内平衡。因此，可以获得 2 个数量级的额外 SERS 增强、更稳定的峰频率和更窄的峰半峰全宽（fwhm），从而确保了极其稳定和可重复的 SERS 信号。通过以良好的信噪比收集浓度低至 0.5 aM（5×10 M）的染料分子的 SERS 光谱，证明了甘油稳定的 3D SERS 热点矩阵具有单分子检测灵敏度。长寿命、超高 SERS 增强和极其稳定的峰形使 3D SERS 热点矩阵成为在复杂基质中检测和分析超低浓度甚至单分子水平分析物的灵敏、实用和可靠工具。
