Department of Chemical Engineering, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609, USA.
Talanta. 2011 May 15;84(3):783-8. doi: 10.1016/j.talanta.2011.02.020. Epub 2011 Feb 19.
Magnetic nanoparticles (MNPs) have been receiving increasing attention because of its great potentials in bioseparation. However, the separation products are difficult to be detected by general method due to their extremely small size. Here, we demonstrate that MNPs can greatly enhance the signal of surface plasmon resonance spectroscopy (SPR). Features of MNPs-aptamer conjugates as a powerful amplification reagent for ultrasensitive immunoassay are reported in this work for the first time. In order to evaluate the sensing ability of MNPs-aptamer conjugates as an amplification reagent, a sandwich SPR sensor is constructed by using thrombin as model analyte. Thrombin, captured by immobilized anti-thrombin aptamer on SPR gold film, is sensitively detected by SPR spectroscopy with a lowest detection limit of 0.017 nM after MNPs-aptamer conjugates is used as amplification reagent. At the same time, the excellent selectivity of the present biosensor is also confirmed by using three kinds of proteins (BSA, human IgM and human IgE) as controls. These results confirm that MNPs is a powerful sandwich element and an excellent amplification reagent for SPR based sandwich immunoassay and SPR has a great potential for the detection of MNPs-based bioseparation products.
磁性纳米粒子（MNPs）因其在生物分离中的巨大潜力而受到越来越多的关注。然而，由于其尺寸极小，分离产物很难用一般方法检测。在这里，我们证明 MNPs 可以大大增强表面等离子体共振光谱（SPR）的信号。本工作首次报道了 MNPs-适配体缀合物作为一种强大的扩增试剂用于超灵敏免疫分析的特性。为了评估 MNPs-适配体缀合物作为扩增试剂的传感能力，我们构建了一个三明治 SPR 传感器，以凝血酶为模型分析物。将凝血酶固定在 SPR 金膜上的抗凝血酶适配体捕获，然后使用 MNPs-aptamer 缀合物作为扩增试剂，通过 SPR 光谱法进行灵敏检测，检测限低至 0.017 nM。同时，还使用三种蛋白质（BSA、人 IgM 和人 IgE）作为对照，证实了本生物传感器具有优异的选择性。这些结果证实 MNPs 是一种强大的三明治元件和用于 SPR 基于三明治免疫分析的优异扩增试剂，并且 SPR 具有用于检测基于 MNPs 的生物分离产物的巨大潜力。
