National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China; University of Chinese Academy of Sciences, Beijing, China.
Biosens Bioelectron. 2015 May 15;67:608-14. doi: 10.1016/j.bios.2014.09.067. Epub 2014 Sep 26.
Detection of Bacillus anthracis in the field, whether as a natural infection or as a biothreat remains challenging. Here we have developed a new lateral-flow immunochromatographic assay (LFIA) for B. anthracis spore detection based on the fact that conjugates of B. anthracis spores and super-paramagnetic particles labeled with antibodies will block the pores of chromatographic strips and form retention lines on the strips, instead of the conventionally reported test lines and control lines in classic LFIA. As a result, this new LFIA can simultaneously realize optical, magnetic and naked-eye detection by analyzing signals from the retention lines. As few as 500-700 pure B. anthracis spores can be recognized with CV values less than 8.31% within 5 min of chromatography and a total time of 20 min. For powdery sample tests, this LFIA can endure interference from 25% (w/v) milk, 10% (w/v) baking soda and 10% (w/v) starch without any sample pre-treatment, and has a corresponding detection limit of 6×10(4) spores/g milk powder, 2×10(5) spores/g starch and 5×10(5) spores/g baking soda. Compared with existing methods, this new approach is very competitive in terms of sensitivity, specificity, cost and ease of operation. This proof-of-concept study can also be extended for detection of many other large-sized analytes.
炭疽杆菌在现场的检测，无论是自然感染还是生物威胁，仍然具有挑战性。在这里，我们基于以下事实开发了一种新的基于侧向流动免疫层析测定（LFIA）的炭疽杆菌孢子检测方法，即炭疽杆菌孢子和标记有抗体的超顺磁颗粒的缀合物会阻塞层析条的孔，并在条上形成保留线，而不是经典 LFIA 中通常报道的测试线和控制线。结果，这种新的 LFIA 可以通过分析保留线的信号，同时实现光学、磁性和肉眼检测。在 5 分钟的色谱分析和总共 20 分钟的时间内，只需 500-700 个纯炭疽杆菌孢子，CV 值小于 8.31%，即可被识别。对于粉末样品测试，这种 LFIA 可以在无需任何样品预处理的情况下耐受 25%（w/v）牛奶、10%（w/v）小苏打和 10%（w/v）淀粉的干扰，对应的检测限分别为 6×10（4）孢子/g 奶粉、2×10（5）孢子/g 淀粉和 5×10（5）孢子/g 小苏打。与现有方法相比，这种新方法在灵敏度、特异性、成本和操作简便性方面具有很强的竞争力。这种概念验证研究也可以扩展到检测许多其他大型分析物。
