title: A mixed self-assembled monolayer-based surface plasmon immunosensor for detection of E. coli O157:H7.
abstract: The sensitivity and specificity of a polyethylene glycol terminated alkanethiol mixed self-assembled monolayers (SAM) on surface plasmon resonance (SPR) immunosensor to detect Escherichia coli O157:H7 is demonstrated. Purified monoclonal (Mabs) or polyclonal antibodies (PAbs) against E. coli O157:H7 were immobilized on an activated sensor chip and direct and sandwich assays were carried to detect E. coli O157:H7. Effect of Protein G based detection and effect of concentrations of primary and secondary antibodies in sandwich assay were investigated. The sensor surface was observed under an optical microscope at various stages of the detection process. The sensor could detect as low as 10(3)CFU/ml of E. coli O157:H7 in a sandwich assay, with high specificity against Salmonella Enteritidis. The detection limit using direct assay and Protein G were 10(6)CFU/ml and 10(4)CFU/ml, respectively. Results indicate that an alkanethiol SAM based SPR biosensor has the potential for rapid and specific detection of E. coli O157:H7, using a sandwich assay.
authors.affiliation: Department of Agricultural and Biological Engineering, The Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Anand
authors.initials: A
authors.lastname: Subramanian
authors.forename: Joseph
authors.initials: J
authors.lastname: Irudayaraj
authors.forename: Thomas
authors.initials: T
authors.lastname: Ryan
mesh_terms: D000936:Antigen-Antibody Complex / Q000032:analysis*; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D020099:Coated Materials, Biocompatible / Q000032:analysis / Q000737:chemistry; D015169:Colony Count, Microbial / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D019453:Escherichia coli O157 / Q000276:immunology / Q000302:isolation & purification*; D007118:Immunoassay / Q000295:instrumentation* / Q000379:methods; D020349:Surface Plasmon Resonance / Q000295:instrumentation* / Q000379:methods
chemical_list: D000936:Antigen-Antibody Complex; D020099:Coated Materials, Biocompatible