npj Science of Food (Oct 2022)

On-site colorimetric detection of Salmonella typhimurium

  • Shengnan Wei,
  • Zhenyue Su,
  • Xiangong Bu,
  • Xuening Shi,
  • Bo Pang,
  • Liang Zhang,
  • Juan Li,
  • Chao Zhao

DOI
https://doi.org/10.1038/s41538-022-00164-0
Journal volume & issue
Vol. 6, no. 1
pp. 1 – 8

Abstract

Read online

Abstract Rapid qualitative and quantitative detection of Salmonella typhimurium (S. typhimurium) takes an important role in ensuring food safety. Herein, a colorimetric assay aptasensor for S. typhimurium utilizing intrinsic peroxidase-like activity of gold nanoparticles embedded spherical covalent organic framework and the affinity and specificity of S. typhimurium-aptamer has been explored. This aptasensor can capture the S. typhimurium via the selective binding effect of aptamer, and the catalytically active sites were shielded. As a result, the colorimetric signals of the 3,3′,5,5′-tetramethylbenzidine-H2O2 system were turned off. Under optimum conditions, the aptasensor gave a linear response over the range of 10 to 107 CFU/mL for S. typhimurium. The detection limit of 7 CFU/mL was obtained within 45 min and was effectively applied to detect S. typhimurium in milk and lake water samples with recoveries in the range from 96.4 to 101.0%. More importantly, combined with a self-developed smartphone-based image analysis system, the proposed aptasensor can be used for point-of-care testing applications.