State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
Jiangxi Province Centers for Disease Control and Prevention, Nanchang 330096, China.
J Dairy Sci. 2017 Jul;100(7):5176-5187. doi: 10.3168/jds.2017-12554. Epub 2017 Apr 27.
Immunochromatographic assays (ICA) are widely used to detect pathogens. In this study, we used traditional gold nanoparticles (GNP), quantum dots (QD), fluorescent nanoparticles (FNP), and europium (Eu) (III) chelate nanoparticles (EuNP) as ICA labels. We first compared the ability of the 4 ICA test strips to quantitatively detect Escherichia coli O157:H7 in milk. We then optimized various parameters influencing the ICA. The sensitivity to E. coli O157:H7 of the GNP-ICA, QD-ICA, FNP-ICA, and EuNP-ICA was 2.5 × 10, 5 × 10, 1.0 × 10, and 5.0 × 10 cfu mL, respectively. The EuNP-ICA exhibited the highest sensitivity. The amounts of monoclonal antibodies (mAb) per GNP-ICA, QD-ICA, FNP-ICA, and EuNP-ICA test strip were 0.16, 0.37, 0.04, and 0.10 μg, respectively. The corresponding coefficients of variation were 7.4 to 15.8%, 10.4 to 18.6%, 2.7 to 7.8%, and 6.9 to 10.5%, respectively. The FNP-ICA required the least mAb per test strip and had the best coefficient of variation. The linear ranges of GNP-ICA, QD-ICA, FNP-ICA, and EuNP-ICA were 1.0 × 10 to 1.0 × 10, 2.5 × 10 to 1.0 × 10, 2.5 × 10 to 2.5 × 10, and 2.5 × 10 to 2.5 × 10 cfu mL, respectively. The FNP-ICA and EuNP-ICA had wider linear ranges than GNP-ICA and QD-ICA. Additionally, the FNP-ICA and EuNP-ICA showed better tolerance than GNP-ICA and QD-ICA in the milk samples. The FNP-ICA and EuNP-ICA showed remarkable potential for detection of pathogens in milk.
免疫胶体金层析法（ICA）广泛用于检测病原体。在本研究中，我们使用传统的金纳米粒子（GNP）、量子点（QD）、荧光纳米粒子（FNP）和铕（Eu）（III）螯合纳米粒子（EuNP）作为 ICA 标记物。我们首先比较了 4 种 ICA 测试条定量检测牛奶中大肠杆菌 O157:H7 的能力。然后，我们优化了影响 ICA 的各种参数。GNP-ICA、QD-ICA、FNP-ICA 和 EuNP-ICA 对大肠杆菌 O157:H7 的灵敏度分别为 2.5×10、5×10、1.0×10 和 5.0×10 cfu mL。EuNP-ICA 的灵敏度最高。GNP-ICA、QD-ICA、FNP-ICA 和 EuNP-ICA 测试条上的单克隆抗体（mAb）量分别为 0.16、0.37、0.04 和 0.10 μg，相应的变异系数分别为 7.4%至 15.8%、10.4%至 18.6%、2.7%至 7.8%和 6.9%至 10.5%。FNP-ICA 每条测试带所需的 mAb 最少，变异系数最好。GNP-ICA、QD-ICA、FNP-ICA 和 EuNP-ICA 的线性范围分别为 1.0×10 至 1.0×10、2.5×10 至 1.0×10、2.5×10 至 2.5×10 和 2.5×10 至 2.5×10 cfu mL。FNP-ICA 和 EuNP-ICA 的线性范围比 GNP-ICA 和 QD-ICA 宽。此外，在牛奶样品中，FNP-ICA 和 EuNP-ICA 的耐受性优于 GNP-ICA 和 QD-ICA。FNP-ICA 和 EuNP-ICA 在检测牛奶中的病原体方面具有显著的潜力。
