Dramatically Enhanced lmmunochromatographic Assay Using Cascade Signal Amplification for Ultrasensitive Detection of Escherichia coil O157:K7 in Milk

文献类型： 外文期刊

第一作者： Fu, Jinmei

作者： Fu, Jinmei;Zhou, Yaofeng;Huang, Xiaolin;Zhang, Wenjing;Wu, Yuhao;Fang, Hao;Xiong, Yonghua;Zhang, Cunzheng

作者机构：

关键词： immunochromatographic assay; cascade signal amplification; in situ gold growth; nanozyme-mediated catalytic deposition; Escherichia coli O157:H7

期刊名称：JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY （ 影响因子：5.279； 五年影响因子：5.269 ）

ISSN： 0021-8561

年卷期： 2020 年 68 卷 4 期

页码：

收录情况： SCI

摘要： The conventional colloidal gold immunochromatographic assay (AuNP-ICA) cannot meet the requirements for the rapid and sensitive detection of Escherichia coli (E. coli) O157:H7 because of its poor sensitivity. Herein, a novel two-step cascade signal amplification strategy that integrates in situ gold growth and nanozyme-mediated catalytic deposition was proposed to enhance the detection sensitivity of conventional AuNP-ICA dramatically. The enhanced strip displayed ultrahigh sensitivity in E. coli O157:H7 detection and had a detection limit of 1.25 x 10(1) CFU/mL, which is approximately 400-fold lower than that of traditional AuNP-ICA (5 x 10(3) CFU/mL). The amplified strip had no background signal in the T-line zone in the absence of E. coli O157:H7 even after one round of cascade signal amplification. The enhanced strip demonstrated excellent selectivity against E. coli O157:H7 with a negligible cross-reaction to nine other common pathogens. Intra-assays and interassays showed that the improved strip has acceptable accuracy and precision for determining E. coli O157:H7. The average recoveries in a real milk sample ranged from 87.33 to 112.15%, and the coefficients of variation were less than 10%. The enhanced strip also showed great potential in detecting a single E. coli O157:H7 cell in a 75 pL solution.

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