title: A sensitive lateral flow biosensor for Escherichia coli O157:H7 detection based on aptamer mediated strand displacement amplification.
abstract: Foodborne diseases caused by pathogens are one of the major problems in food safety. Convenient and sensitive point-of-care rapid diagnostic tests for food-borne pathogens have been a long-felt need of clinicians. Commonly used methods for pathogen detection rely on conventional culture-based tests, antibody-based assays and polymerase chain reaction (PCR)-based techniques. These methods are costly, laborious and time-consuming. Herein, we present a simple and sensitive aptamer based biosensor for rapid detection of Escherichia coli O157:H7 (E. coli O157:H7). In this assay, two different aptamers specific for the outmembrane of E. coli O157:H7 were used. One of the aptamers was used for magnetic bead enrichment, and the other was used as a signal reporter for this pathogen, which was amplified by isothermal strand displacement amplification (SDA) and further detected by a lateral flow biosensor. Only the captured aptamers on cell membrane were amplified, limitations of conventional DNA amplification based method such as false-positive can be largely reduced. The generated signals (red bands on the test zone of a lateral flow strip) can be unambiguously read out by the naked eye. As low as 10 colony forming units (CFU) of E. coli O157:H7 were detected in this study. Without DNA extraction, the reduced handling and simpler equipment requirement render this assay a simple and rapid alternative to conventional methods.
authors.affiliation: College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wu
authors.affiliation: Key Laboratory of Regenerative Biology, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.
authors.forename: Shiming
authors.initials: S
authors.lastname: Zhao
authors.affiliation: Yueyang Institute for Food and Drug Control, Yueyang 430198, China.
authors.forename: Yiping
authors.initials: Y
authors.lastname: Mao
authors.affiliation: Affiliated Tumor Hospital of Guangzhou Medical University, Guangzhou 510095, China.
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Fang
authors.affiliation: Key Laboratory of Regenerative Biology, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.
authors.forename: Xuewen
authors.initials: X
authors.lastname: Lu
authors.affiliation: Key Laboratory of Regenerative Biology, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China. Electronic address: zeng6@yahoo.com.
authors.forename: Lingwen
authors.initials: L
authors.lastname: Zeng
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques; D019453:Escherichia coli O157 / Q000302:isolation & purification*
chemical_list: D052157:Aptamers, Nucleotide
keywords: Aptamer; Escherichia coli O157:H7; Isothermal strand displacement amplification; Lateral flow biosensor