National Physical Laboratory, Hampton Road, Teddington, Middlesex, TW11 0LW United Kingdom.
Anal Chem. 2012 Oct 2;84(19):8246-52. doi: 10.1021/ac301566k. Epub 2012 Sep 21.
Here we describe scattering based signal suppression artifacts encountered while developing multiplex lateral flow (LF) immunoassay using surface enhanced Raman spectroscopy (SERS) "nanotags" as analyte labels. Using these SERS nanotags, we have produced a quantitative test for inflammation biomarkers that is transferable to the point of care (POC). The SERS assay shows similar performance when compared with a fluorescent nanoparticle POC test. Here, using cardiac and inflammation biomarkers, we highlight the need to carefully optimize the concentration of assay components when using SERS nanotags and a single-line multiplexing approach. We show that in certain circumstances the SERS signal may be suppressed, leading to a significant underestimation of the analyte concentrations. Using electron microscopy and optical spectroscopy, we demonstrate that the error in the measurement is associated with the light scattering properties of the nanotags. These findings will be applicable to other nanoparticle labels with high light scattering coefficients. Through careful modification of the assay to reduce the impact of light scattering, it is possible to produce quantitative assays, but potentially at the expense of multiplexing capability and assay sensitivity.
在这里，我们描述了在使用表面增强拉曼光谱（SERS）“纳米标签”作为分析物标记物开发多重侧向流动（LF）免疫分析时遇到的基于散射的信号抑制伪影。使用这些 SERS 纳米标签，我们已经开发出了一种可用于即时护理（POC）的炎症生物标志物的定量测试。与荧光纳米颗粒 POC 测试相比，SERS 测定具有相似的性能。在这里，我们使用心脏和炎症生物标志物强调了在使用 SERS 纳米标签和单线多重化方法时需要仔细优化测定成分的浓度。我们表明，在某些情况下，SERS 信号可能会受到抑制，从而导致对分析物浓度的严重低估。通过电子显微镜和光谱学，我们证明了测量中的误差与纳米标签的光散射特性有关。这些发现将适用于具有高光散射系数的其他纳米颗粒标记物。通过仔细修改测定以减少光散射的影响，可以产生定量测定，但可能会牺牲多重化能力和测定灵敏度。
