Whole-bacterium SELEX of DNA aptamers for rapid detection of E.coli O157:H7 using a QCM sensor

Xiaofan Yu; Fang Chen; Ronghui Wang; Yanbin Li

doi:10.1016/j.jbiotec.2017.12.011

Whole-bacterium SELEX of DNA aptamers for rapid detection of E.coli O157:H7 using a QCM sensor

J Biotechnol. 2018 Jan 20:266:39-49. doi: 10.1016/j.jbiotec.2017.12.011. Epub 2017 Dec 12.

Authors

Xiaofan Yu¹, Fang Chen², Ronghui Wang³, Yanbin Li⁴

Affiliations

¹ Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR, 72701, USA.
² Rice Research Center, Shenyang Agricultural University, Shenyang, China.
³ Department of Biological & Agricultural Engineering, University of Arkansas, Fayetteville, AR, 72701, USA.
⁴ Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR, 72701, USA; Department of Biological & Agricultural Engineering, University of Arkansas, Fayetteville, AR, 72701, USA; Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR, 72701, USA. Electronic address: yanbinli@uark.edu.

PMID: 29242148
DOI: 10.1016/j.jbiotec.2017.12.011

Abstract

The rapid detection of foodborne pathogens is critical to ensure food safety. The objective of this study is to select aptamers specifically bound to Escherichia coli O157:H7 using the whole-bacterium SELEX (Systematic Evolution of Ligands by Exponential Enrichment) and apply the selected aptamer to a QCM (quartz crystal microbalance) sensor for rapid and sensitive detection of target bacteria. A total of 19 rounds of selection against live E. coli O157:H7 and 6 rounds of counter selection against a mixture of Staphylococcus aureus, Listeria monocytogenes, and Salmonella Typhimurium, were performed. The aptamer pool from the last round was cloned and sequenced. One sequence S1 that appeared 16 times was characterized and a dissociation constant (K_d) of 10.30nM was obtained. Subsequently, a QCM aptasensor was developed for the rapid detection of E. coli O157:H7. The limit of detection (LOD) and the detection time of the aptasensor was determined to be 1.46×10³ CFU/ml and 50min, respectively. This study demonstrated that the ssDNA aptamer selected by the whole-bacterium SELEX possessed higher sensitivity than previous work and the potential use of the constructed QCM aptasensor in rapid screening of foodborne pathogens.

Keywords: DNA aptamer; E. coli O157:H7; QCM sensor; Whole-bacterium SELEX.

MeSH terms

Aptamers, Nucleotide / chemistry*
Escherichia coli O157*
Food Microbiology / methods*
Quartz Crystal Microbalance Techniques*
SELEX Aptamer Technique*

Substances

Aptamers, Nucleotide