Anal Chem. 2010 Oct 1;82(19):8042-6. doi: 10.1021/ac102127p.
Despite its high refractive index sensitivity, localized surface plasmon resonance (LSPR) spectroscopy has been generally restricted to large biological analytes. Sensing of smaller molecules is a compelling target for this technique; in particular, LSPR spectroscopy could be utilized to detect hazardous or toxic gases and manage industrial processes involving gaseous chemicals. Here, we report sensing of pure gases over Ag nanoparticles using LSPR spectroscopy, where the detected changes in bulk refractive index are <5 × 10(-4) refractive index units (RIU). We further demonstrate a novel strategy for amplifying the sensing signal by coating the plasmonic substrate with a metal-organic framework (MOF) material. Cu(3)(BTC)(2)(H(2)O)(3), BTC = benzenetricarboxylate, was grown on Ag nanoparticles using a layer-by-layer method in order to control the MOF thickness, which we show greatly affects the sensor response. Preferential concentration of CO(2) within the MOF pores produces a 14-fold signal enhancement for CO(2) sensing. In principle, MOFs can be tailored for sorbing different analytes, making them ideal materials for this amplification strategy. Because the sensing signal originates in the nanoparticle extinction spectrum and not in the MOF itself, this comprises a generalizable sensing scheme applicable to any porous MOF and any analyte.
尽管局部表面等离子体共振（LSPR）光谱具有很高的折射率灵敏度，但它通常仅限于大型生物分析物。对于这种技术来说，检测更小的分子是一个非常吸引人的目标；特别是，LSPR 光谱可以用于检测危险或有毒气体，并管理涉及气态化学品的工业过程。在这里，我们报告了使用 LSPR 光谱检测纯气体的情况，其中检测到的体折射率变化<5×10(-4)折射率单位（RIU）。我们进一步展示了一种通过用金属-有机骨架（MOF）材料涂覆等离子体基底来放大传感信号的新策略。使用逐层方法在 Ag 纳米颗粒上生长 Cu(3)(BTC)(2)(H(2)O)(3)，BTC = 苯三甲酸，以控制 MOF 的厚度，我们表明这对传感器的响应有很大的影响。CO(2)在 MOF 孔内的优先浓缩产生了 CO(2)传感的 14 倍信号增强。原则上，可以根据需要对 MOF 进行定制以吸附不同的分析物，因此它们是这种放大策略的理想材料。由于传感信号源自纳米颗粒的消光谱，而不是 MOF 本身，因此这构成了一种适用于任何多孔 MOF 和任何分析物的可推广的传感方案。
