Immunomagnetic separation and size-based detection of Escherichia coli O157 at the meniscus of a membrane strip. Issue 46 (23rd July 2018)

• Record Type: Journal Article
• Authors: Lee, Hyeonjeong; Hwang, Jeongin; Park, Yunsung; Kwon, Donghoon; Lee, Sanghee; Kang, Inseok; Jeon, Sangmin
• Is Part Of: RSC advances. Volume 8:Issue 46(2018)
• Page Start: 26266
• Page End: 26270
• Publication Date: 2018-07-23
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c8ra04739a
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : E. coli –Au/MNC complexes accumulate at the meniscus of the test strip where the flow velocity reaches a maximum. Abstract : We developed a facile method for the detection of pathogenic bacteria using gold-coated magnetic nanoparticle clusters (Au@MNCs) and porous nitrocellulose strips. Au@MNCs were synthesized and functionalized with half-fragments of Escherichia coli O157 antibodies. After the nanoparticles were used to capture E. coli O157 in milk and dispersed in a buffer solution, one end of a test strip was dipped into the solution. Due to the size difference between the E. coli –Au@MNC complexes (approximately 1 μm) and free Au@MNCs (approximately 180 nm), only E. coli –Au@MNC complexes accumulated at the meniscus of the test strip and induced a color change. The color intensity of the meniscus was proportional to the E. coli concentration, and the detection limit for E. coli in milk was 10 3 CFU mL −1 by the naked eye. The presence of E. coli –Au@MNC complexes at the meniscus was confirmed using a real-time PCR assay. The developed method was highly selective for E. coli when compared with Salmonella typhimurium, Listeria monocytogenes, and Staphylococcus aureus .