title: Detection of Salmonella typhimurium using an electrochemical immunosensor.
abstract: An electrochemical immunosensor based on screen-printed gold working electrode with onboard carbon counter and silver-silver chloride pseudo-reference electrode for Salmonella typhimurium detection is described in this paper. Monoclonal anti-S. typhimurium antibody was immobilized using physical and covalent immobilization via amine coupling of carboxymethyldextran on the surface of the gold working electrode. A direct sandwich enzyme-linked immunosorbent assays (ELISA) format was then developed and optimized using a polyclonal anti-Salmonella antibodies conjugated to horseradish peroxidase (HRP) as the enzyme label. 3,3',5,5'-Tetramethylbenzidine dihydrochloride (TMB)/H(2)O(2) was used as the enzyme mediator/substrate system. Electrochemical detection was conducted using chronoamperometry at -200 mV vs. onboard screen-printed Ag-AgCl pseudo-reference electrode. The applied potential was selected through the study of the electrochemical behaviour of bare gold electrode with TMB-H(2)O(2)-IgG-HRP system. S. typhimurium detection of 5x10(3) cells ml(-1) and approximately 20 cells ml(-1) was achieved respectively for physical and covalent antibody immobilization. The developed sensor was then compared to a commercial ELISA kit and a chromogenic agar plating method for meat samples analysis. The sensor format shows a promising technology for simple and sensitive detection system for Salmonella contamination. Rapid detection of Salmonella is a key to the prevention and identification of problems related to health and safety.
authors.affiliation: Cranfield Health, Cranfield University, Cranfield, Bedfordshire, MK43 0AL, United Kingdom.
authors.forename: Faridah
authors.initials: F
authors.lastname: Salam
authors.forename: Ibtisam E
authors.initials: IE
authors.lastname: Tothill
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D015169:Colony Count, Microbial / Q000295:instrumentation*; D004563:Electrochemistry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007118:Immunoassay / Q000295:instrumentation*; D015203:Reproducibility of Results; D012486:Salmonella typhimurium / Q000302:isolation & purification*; D012680:Sensitivity and Specificity