title: Enrichment and detection of Escherichia coli O157:H7 from water samples using an antibody modified microfluidic chip.
abstract: Low abundant (<100 cells mL(-1)) E. coli O157:H7 cells were isolated and enriched from environmental water samples using a microfluidic chip. The poly(methylmethacrylate), PMMA, chip contained 8 devices, each equipped with 16 curvilinear high aspect ratio channels that were covalently decorated with polyclonal anti-O157 antibodies (pAb) and could search for rare cells through a pAb mediated process. The chip could process independently 8 different samples or one sample using 8 different parallel inputs to increase volume processing throughput. After cell enrichment, cells were released and enumerated using benchtop real-time quantitative polymerase chain reaction (PCR), targeting genes which effectively discriminated the O157:H7 serotype from other nonpathogenic bacteria. The recovery of target cells from water samples was determined to be approximately 72%, and the limit-of-detection was found to be 6 colony forming units (cfu) using the slt1 gene as a reporter. We subsequently performed analysis of lake and wastewater samples. The simplicity in manufacturing and ease of operation makes this device attractive for the selection of pathogenic species from a variety of water supplies suspected of containing bacterial pathogens at extremely low frequencies.
authors.affiliation: Center for Bio-Modular Multi-Scale Systems, Louisiana State University, 8000 G.SRI Road, Bldg. 3100, Baton Rouge, Louisiana 70820-7403, USA.
authors.forename: Udara
authors.initials: U
authors.lastname: Dharmasiri
authors.forename: Małgorzata A
authors.initials: MA
authors.lastname: Witek
authors.forename: Andre A
authors.initials: AA
authors.lastname: Adams
authors.forename: John K
authors.initials: JK
authors.lastname: Osiri
authors.forename: Mateusz L
authors.initials: ML
authors.lastname: Hupert
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Bianchi
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Roelke
authors.forename: Steven A
authors.initials: SA
authors.lastname: Soper
mesh_terms: D055910:Antibodies, Immobilized / Q000276:immunology / Q000378:metabolism*; D019453:Escherichia coli O157 / Q000302:isolation & purification*; D046210:Microfluidic Analytical Techniques / Q000379:methods*; D008856:Microscopy, Fluorescence; D016133:Polymerase Chain Reaction; D019904:Polymethyl Methacrylate / Q000737:chemistry; D012703:Serotyping; D014871:Water Microbiology
chemical_list: D055910:Antibodies, Immobilized; D019904:Polymethyl Methacrylate