title: Aptamer-based impedimetric sensor for bacterial typing.
abstract: The development of an aptamer-based impedimetric sensor for typing of bacteria (AIST-B) is presented. Highly specific DNA aptamers to Salmonella enteritidis were selected via Cell-SELEX technique. Twelve rounds of selection were performed; each comprises a positive selection step against S. enteritidis and a negative selection step against a mixture of related pathogens, including Salmonella typhimurium, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Citrobacter freundii, to ensure the species-specificity of the selected aptamers. After sequencing of the pool showing the highest binding affinity to S. enteritidis, a DNA sequence of high affinity to the bacteria was integrated into an impedimetric sensor via self-assembly onto a gold nanoparticles-modified screen-printed carbon electrode (GNPs-SPCE). Remarkably, this aptasensor is highly selective and can successfully detect S. enteritidis down to 600 CFU mL(-1) (equivalent to 18 CFU in 30 μL assay volume) in 10 min and distinguish it from other Salmonella species, including S. typhimurium and S. choleraesuis. This report is envisaged to open a new venue for the aptamer-based typing of a variety of microorganisms using a rapid, economic, and label-free electrochemical platform.
authors.affiliation: Department of Chemistry, University of Ottawa, 10 Marie Curie, Ottawa, Ontario K1N 6N5, Canada.
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Labib
authors.forename: Anna S
authors.initials: AS
authors.lastname: Zamay
authors.forename: Olga S
authors.initials: OS
authors.lastname: Kolovskaya
authors.forename: Irina T
authors.initials: IT
authors.lastname: Reshetneva
authors.forename: Galina S
authors.initials: GS
authors.lastname: Zamay
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Kibbee
authors.forename: Syed A
authors.initials: SA
authors.lastname: Sattar
authors.forename: Tatiana N
authors.initials: TN
authors.lastname: Zamay
authors.forename: Maxim V
authors.initials: MV
authors.lastname: Berezovski
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D001419:Bacteria / Q000302:isolation & purification*; D015374:Biosensing Techniques / Q000295:instrumentation
chemical_list: D052157:Aptamers, Nucleotide