College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, PR China.
Hangzhou Institute for Food and Drug Control, Hangzhou 310022, PR China.
Anal Chem. 2022 Aug 2;94(30):10865-10873. doi: 10.1021/acs.analchem.2c02020. Epub 2022 Jul 19.
Immunological detection of small molecules in a point-of-care (POC) format is of great significance yet remains challenging for accurate visual discrimination and quantitative analysis. Here, we report a novel hue recognition competitive fluorescent lateral flow immunoassay (HCLFIA) strip that allows both visual and quantitative detection of aflatoxin M (AFM). The HCLFIA strip works on the basis of the ratiometric change of emission, arising from the overlap of fluorescence signals of two nanocomposites tagged with probe antibodies and coated antigens. A visually discernible orange-red-to-green fluorescence color change allows the naked eye semiquantitative readout of AFM around the threshold concentration (0.05 ng mL), yielding a visible detection limit of 0.02 ng mL. Moreover, using a custom smartphone-based device and color chart analysis, ultrasensitive quantitative detection of AFM can be achieved with a low limit of detection at 0.0012 ng mL, which is considerably better than those of the previously reported colorimetric and fluorescent strips. The accuracy performed in spiked milk samples ranged from 97.91 to 113.12% with a coefficient of variation below 7.8%, showing good consistency with the results from isotope dilution liquid chromatography-tandem mass spectrometry. Thanks to the unique hue recognition scheme, the HCLFIA strip holds great potential for POC detection of small molecules.
在即时检测（POC）格式中对小分子进行免疫学检测具有重要意义，但对于准确的目视判别和定量分析仍然具有挑战性。在这里，我们报告了一种新颖的色调识别竞争荧光侧向流动免疫分析（HCLFIA）条带，可用于可视化和定量检测黄曲霉毒素 M（AFM）。HCLFIA 条带基于两种纳米复合材料的发射比变化原理工作，这两种纳米复合材料分别标记有探针抗体和包被抗原。橙色红色到绿色荧光颜色的肉眼可见变化可实现 AFM 的半定量目视读出，在阈值浓度（0.05 ng mL）左右，产生可见检测限为 0.02 ng mL。此外，使用定制的基于智能手机的设备和色标分析，可以实现 AFM 的超灵敏定量检测，检测限低至 0.0012 ng mL，明显优于先前报道的比色和荧光条带。在添加牛奶样品中的准确性范围为 97.91%至 113.12%，变异系数低于 7.8%，与同位素稀释液相色谱-串联质谱的结果具有良好的一致性。由于独特的色调识别方案，HCLFIA 条带在小分子的 POC 检测中具有很大的潜力。
