Department of Biotechnology, University of Turku, Turku, Finland.
Department of Biotechnology, University of Turku, Turku, Finland.
J Immunol Methods. 2019 Feb;465:39-44. doi: 10.1016/j.jim.2018.12.001. Epub 2018 Dec 4.
Lateral flow (LF) immunoassays are commonly used for point-of-care testing and typically incorporate visually read reporters, such as gold particles. To improve sensitivity and develop quantitative LF immunoassays, visual reporters can be replaced by fluorescent reporters detected by an instrument. In this study, we used fluorescent europium(III) chelate doped nanoparticle (Eu-np) reporters to develop a quantitative high-sensitivity LF immunoassay for free prostate specific antigen (fPSA). Furthermore, we tested different simplified formats of the assay and the effect of different modifiable parameters on the detection limit of the assay: dynamic range, assay duration and number of assay steps. The molar detection limits of the different assay formats were compared with published detection limits of LF immunoassays with different reporters. The cutoff was calculated from 11 female serum samples. The detection limit of the sensitivity optimized fPSA assay with fPSA spiked into pooled female serum was 0.01 ng/ml, which is approximately 100-fold lower than the most sensitive gold particle LF assays and 10-fold lower than other Eu-np and carbon nanoparticle based LF immunoassays. Thus, Eu-np reporters can be used to develop highly sensitive and quantitative LF immunoassays.
侧向流动 (LF) 免疫分析通常用于即时检测，通常采用肉眼可读的报告器，如金颗粒。为了提高灵敏度并开发定量 LF 免疫分析，视觉报告器可以被仪器检测的荧光报告器取代。在这项研究中，我们使用荧光铕 (III) 螯合物掺杂纳米颗粒 (Eu-np) 报告器开发了一种用于游离前列腺特异性抗原 (fPSA) 的定量高灵敏度 LF 免疫分析。此外，我们测试了不同简化的检测格式以及不同可修改参数对检测限的影响：动态范围、检测持续时间和检测步骤数量。不同检测格式的摩尔检测限与使用不同报告器的 LF 免疫分析的已发表检测限进行了比较。从 11 名女性血清样本中计算出了截止值。用混合女性血清中添加的 fPSA 优化灵敏度的 fPSA 检测的检测限为 0.01ng/ml，大约比最灵敏的金颗粒 LF 检测低 100 倍，比其他 Eu-np 和基于碳纳米颗粒的 LF 免疫分析低 10 倍。因此，Eu-np 报告器可用于开发高灵敏度和定量 LF 免疫分析。
