Key Laboratory for Atomic and Molecular Nanosciences of Ministry of Education (MOE), Department of Chemistry, Tsinghua University, Tsinghua Yuan, Beijing 100084, PR China.
Talanta. 2010 Nov 15;83(1):48-54. doi: 10.1016/j.talanta.2010.08.037. Epub 2010 Sep 27.
A sensitive sandwich type immunoassay has been proposed with the detection by inductively coupled plasma mass spectrometry (ICP-MS) in a single particle mode (time resolved analysis). The signal induced by the flash of ions ((197)Au(+)) due to the ionization of single Au-nanoparticle (Au-NP) label in the plasma torch can be measured by the mass spectrometer. The frequency of the transient signals is proportional to the concentration of Au-NPs labels. Characteristics of the signals obtained from Au-NPs of 20, 45 and 80 nm in diameters were discussed. The analytical figures for the determination of Au-labeled IgG using ICP-MS in conventional integral mode and single particle mode were compared in detail. Rabbit-anti-human IgG was used as a model analyte in the sandwich immunoassay. A detection limit (3 σ) of 0.1 ng mL(-1) was obtained for rabbit-anti-human IgG after immunoreactions, with a linear range of 0.3-10 ng mL(-1) and a RSD of 8.1% (2.0 ng mL(-1)). Finally, the proposed method was successfully applied to spiked rabbit-anti-human IgG samples and rabbit-anti-human serum samples. The method resulted to be a highly sensitive ICP-MS based sandwich type immunoassay.
提出了一种灵敏的三明治型免疫分析方法，采用电感耦合等离子体质谱（ICP-MS）在单颗粒模式（时间分辨分析）下进行检测。等离子体火炬中单个金纳米粒子（Au-NP）标记物的离子（(197)Au(+)）电离所产生的离子闪烁会引发质谱仪的信号。瞬变信号的频率与 Au-NP 标记物的浓度成正比。讨论了直径为 20、45 和 80nm 的 Au-NP 获得的信号特征。详细比较了使用常规积分模式和单颗粒模式的 ICP-MS 测定 Au 标记 IgG 的分析性能。兔抗人 IgG 被用作三明治免疫分析中的模式分析物。免疫反应后，兔抗人 IgG 的检测限（3σ）为 0.1ng/mL，线性范围为 0.3-10ng/mL，相对标准偏差（RSD）为 8.1%（2.0ng/mL）。最后，该方法成功应用于兔抗人 IgG 加标样品和兔抗人血清样品。结果表明，该方法是一种基于 ICP-MS 的高灵敏度三明治型免疫分析方法。
