Novel ELISA based on fluorescent quenching of DNA-stabilized silver nanoclusters for detecting E. coli O157:H7.

Journal: Food chemistry
PMID: 30658771

Abstract

Escherichia coli O157:H7 (E. coli O157:H7) is a potential threat to human health; thus, a rapid and sensitive method for detecting it is necessary. We designed a single-stranded DNA that contained an appended block and anchoring block. The appended block acted as a scaffold to prepare fluorescent Ag nanoclusters (AgNCs). The anchoring block contained Poly A, which bound with the surface of gold nanoparticles to quench the fluorescence of AgNCs. An interesting ELISA approach for detecting E. coli O157:H7 was established via fluorescent quenching of DNA-stabilized AgNCs by using a sandwich complex. The changes in fluorescence intensity of AgNCs were used to quantitatively detect E. coli O157:H7. The sensitivity for detecting E. coli O157:H7 reached 1.905 × 10 CFU/mL with a good linear range. Compared with conventional ELISA, the sensitivity of this technique increased by 30-fold. Moreover, this method demonstrated specificity and reproducibility and could be used in food samples.

Authors

  • Chun Wang
    Department of Obstetrics and Gynecology, Peking University Shenzhen Hospital, Shenzhen, China.
  • Keyu Xing
    State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
  • Ganggang Zhang
    State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
  • Meifang Yuan
    State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
  • Shaolan Xu
    State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
  • Daofeng Liu
    Jiangxi Province Center for Disease Control and Prevention, Nanchang 330047, China.
  • Wenyao Chen
    State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
  • Juan Peng
    State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
  • Song Hu
    State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
  • Wei-Hua Lai
    State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China. Electronic address: talktolaiwh@163.com.

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