Xia Xiaohu, Xu Ye, Zhao Xilin, Li Qingge
Molecular Diagnostics Laboratory, Department of Biomedical Sciences and the Key Laboratory of the Ministry of Education for Cell Biology and Tumor Cell Engineering, School of Life Sciences, Xiamen University, Xiamen, Fujian, China.
Clin Chem. 2009 Jan;55(1):179-82. doi: 10.1373/clinchem.2008.114561. Epub 2008 Oct 30.
Despite their ease of use, lateral flow immunoassays (LFIAs) often suffer from poor quantitative discrimination and low analytical sensitivity. We explored the use of a novel class of europium chelate-loaded silica nanoparticles as labels to overcome these limitations.
Antibodies were covalently conjugated onto europium chelate-loaded silica nanoparticles with dextran as a linker. The resulting conjugates were used as labels in LFIA for detection of hepatitis B surface antigen (HBsAg). We performed quantification with a digital camera and Adobe Photoshop software. We also used 286 clinical samples to compare the proposed method with a quantitative ELISA.
A detection limit of 0.03 microg/L was achieved, which was 100 times lower than the colloidal gold-based LFIAs and lower than ELISA. A precise quantitative dose-response curve was obtained, and the linear measurement range was 0.05-3.13 microg/L, within which the CVs were 2.3%-10.4%. Regression analysis of LFIA on ELISA results gave: log (LFIA) = -0.14 log (ELISA) + 1.03 microg/L with r = 0.99 for the quantification of HBsAg in 35 positive serum samples. Complete agreement was observed for the qualitative comparison of 286 clinical samples assayed with LFIA and ELISA.
Europium chelate-loaded silica nanoparticle labels have great potential to improve LFIAs, making them useful not only for simple screening applications but also for more sensitive and quantitative immunoassays.
尽管侧向流动免疫分析（LFIA）使用方便，但常常存在定量辨别能力差和分析灵敏度低的问题。我们探索使用一类新型的负载铕螯合物的二氧化硅纳米颗粒作为标记物来克服这些局限性。
抗体通过葡聚糖作为连接剂共价偶联到负载铕螯合物的二氧化硅纳米颗粒上。所得偶联物用作LFIA中检测乙型肝炎表面抗原（HBsAg）的标记物。我们使用数码相机和Adobe Photoshop软件进行定量分析。我们还使用286份临床样本将所提出的方法与定量酶联免疫吸附测定（ELISA）进行比较。
实现了0.03μg/L的检测限，这比基于胶体金的LFIA低100倍，且低于ELISA。获得了精确的定量剂量 - 反应曲线，线性测量范围为0.05 - 3.13μg/L，在此范围内变异系数（CVs）为2.3% - 10.4%。对35份阳性血清样本中HBsAg定量的LFIA与ELISA结果进行回归分析得到：log（LFIA） = -0.14 log（ELISA） + 1.03μg/L，r = 0.99。对用LFIA和ELISA检测的286份临床样本进行定性比较时观察到完全一致。
负载铕螯合物的二氧化硅纳米颗粒标记物在改进LFIA方面具有巨大潜力，使其不仅适用于简单的筛查应用，还适用于更灵敏和定量的免疫分析。
