Sample-in-answer-out colorimetric detection of Salmonella typhimurium using non-enzymatic cascade amplification

Hong Duan; Wuzhen Qi; Siyuan Wang; Lingyan Zheng; Jing Yuan; Jianhan Lin

doi:10.1016/j.aca.2022.339850

Sample-in-answer-out colorimetric detection of Salmonella typhimurium using non-enzymatic cascade amplification

Anal Chim Acta. 2022 Jul 25:1218:339850. doi: 10.1016/j.aca.2022.339850. Epub 2022 May 25.

Authors

Hong Duan¹, Wuzhen Qi¹, Siyuan Wang¹, Lingyan Zheng², Jing Yuan¹, Jianhan Lin³

Affiliations

¹ Key Laboratory of Agricultural Information Acquisition Technology, Ministry of Agriculture and Rural Affairs, China Agricultural University, Beijing, 100083, China.
² Key Laboratory of Agricultural Information Acquisition Technology, Ministry of Agriculture and Rural Affairs, China Agricultural University, Beijing, 100083, China; Beijing Engineering and Technology Research Center of Food Additives, Beijing Technology & Business University, Beijing, 100048, China.
³ Key Laboratory of Agricultural Information Acquisition Technology, Ministry of Agriculture and Rural Affairs, China Agricultural University, Beijing, 100083, China. Electronic address: jianhan@cau.edu.cn.

PMID: 35701035
DOI: 10.1016/j.aca.2022.339850

Abstract

Rapid and sensitive screening of pathogens is a key to prevent the outbreak of foodborne illnesses. Herein, a new colorimetric immunoassay was proposed based on the release of Ag⁺ ions from AgNPs and the inhibition of PtNPs, and its supporting microfluidic platform was developed to automatically perform the whole bacterial detection procedure using Raspberry Pi and smartphone App. First, the immune AgNPs and magnetic nanobeads (MNBs) were used to conjugate with Salmonella typhimurium. Then, H₂O₂ was used to etch the AgNPs for release Ag⁺ ions. Finally, the colorimetric signal was greatly diminished because of the specific and efficient inhibition of Ag⁺ toward the peroxidase-like activity of the PtNPs. This colorimetric immunoassay showed a good specificity and an ultralow detection limit of 16.8 CFU/mL, which was about 3 orders of magnitude improvement compared with conventional ELISA, and the averaged recovery for the spiked chicken samples was 95.6%. The combination of this immunoassay with this microfluidic platform might be promising for rapid and sensitive screening of foodborne pathogens to ensure food safety.

Keywords: Colorimetric immunoassay; Microfluidic platform; Platinum inhibition; Salmonella typhimurium; Sample-in-answer-out detection.

MeSH terms

Biosensing Techniques*
Colorimetry* / methods
Food Safety
Hydrogen Peroxide
Immunoassay / methods
Limit of Detection
Salmonella typhimurium

Substances

Hydrogen Peroxide