title: Piezoelectric immunosensor for direct and rapid detection of staphylococcal enterotoxin A (SEA) at the ng level.
abstract: A direct, label-free immunosensor was designed for the rapid detection and quantification of staphylococcal enterotoxin A (SEA) in buffered solutions using quartz crystal microbalance with dissipation (QCM-D) as transduction method. The sensing layer including the anti-SEA antibody was constructed by chemisorption of a self-assembled monolayer of cysteamine on the gold electrodes placed over the quartz crystal sensor followed by activation of the surface amino groups with the rigid homobifunctional cross-linker 1,4-phenylene diisothiocyanate (PDITC) and covalent linking of binding protein (protein A or protein G). Four anti-SEA antibodies (two of which from commercial source) have been selected to set up the most sensitive detection device. With the optimized sensing layer, a standard curve for the direct assay of SEA was established from QCM-D responses within a working range of 50-1000 or 2000 ngml(-1) with a detection limit of 20 ngml(-1). The total time for analysis was 15 min. Using a sandwich type assay, the response was ca. twice higher and consequently the lowest measurable concentration dropped down to 7 ngml(-1) for a total assay time of 25 min.
authors.affiliation: Chimie ParisTech, Laboratoire Charles Friedel, F-75005 Paris, France. michele-salmain@chimie-paristech.fr
authors.forename: Michèle
authors.initials: M
authors.lastname: Salmain
authors.forename: Mahsa
authors.initials: M
authors.lastname: Ghasemi
authors.forename: Souhir
authors.initials: S
authors.lastname: Boujday
authors.forename: Jolanda
authors.initials: J
authors.lastname: Spadavecchia
authors.forename: Clarisse
authors.initials: C
authors.lastname: Técher
authors.forename: Florence
authors.initials: F
authors.lastname: Val
authors.forename: Vincent
authors.initials: V
authors.lastname: Le Moigne
authors.forename: Michel
authors.initials: M
authors.lastname: Gautier
authors.forename: Romain
authors.initials: R
authors.lastname: Briandet
authors.forename: Claire-Marie
authors.initials: CM
authors.lastname: Pradier
mesh_terms: D000907:Antibodies, Bacterial; D055910:Antibodies, Immobilized; D015374:Biosensing Techniques / Q000379:methods* / Q000592:standards / Q000706:statistics & numerical data; D004768:Enterotoxins / Q000032:analysis* / Q000276:immunology / Q000592:standards; D005506:Food Contamination / Q000032:analysis; D005516:Food Microbiology; D007118:Immunoassay / Q000379:methods / Q000592:standards / Q000706:statistics & numerical data; D036103:Nanotechnology; D058525:Quartz Crystal Microbalance Techniques / Q000379:methods / Q000592:standards / Q000706:statistics & numerical data
chemical_list: D000907:Antibodies, Bacterial; D055910:Antibodies, Immobilized; D004768:Enterotoxins; C026066:enterotoxin A, Staphylococcal