Enzyme-linked immunomagnetic electrochemical detection of Salmonella typhimurium

• Published in: Journal of immunological methods Vol. 195; no. 1; pp. 15 - 25
• Main Authors: Gehring, Andrew G., Gerald Crawford, C., Mazenko, Ralph S., Van Houten, Lisa J., Brewster, Jeffrey D.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 09-09-1996; Elsevier
• Subjects: Bacteriological methods and techniques used in bacteriology; Bacteriology; Bacterium; Biological and medical sciences; Detection; Electrochemistry; Fundamental and applied biological sciences. Psychology; Immunoenzyme Techniques; Immunomagnetic; Immunomagnetic Separation; Magnetic bead; Microbiology; Salmonella; Salmonella typhimurium; Salmonella typhimurium - immunology; Salmonella typhimurium - isolation & purification; Magnetic bead; Salmonella; Bacterium; pAPP; TBS; ELIME; ELIMC; Electrochemistry; Immunomagnetic; Detection; AP; IMB; Performance evaluation; Rapid technique; Immunomagnetic method; Bacteria; Enzyme immunoassay; Salmonella typhimurium; Enterobacteriaceae
• ISSN: 0022-1759; 1872-7905
• DOI: 10.1016/0022-1759(96)00076-2

There is a need for rapid methods to detect pathogenic bacteria in food products as alternatives to the current laborious and time-consuming culture procedures. We report a microbial detection technique that combines the selectivity of antibody-coated superparamagnetic beads with the rapidity and sensitivity of electrochemical detection in a format termed enzyme-linked immunomagnetic electrochemistry. In it,
Salmonella typhimurium were sandwiched between antibody-coated magnetic beads and an enzyme-conjugated antibody. With the aid of a magnet, the beads (with or without bound bacteria) were localized onto the surface of disposable graphite ink electrodes in a multi-well plate format. Enzyme substrate was added and conversion of substrate to an electroactive product was measured using electrochemical detection. The electrochemical response was directly proportional to the number of captured bacteria. Using this technique, a minimum detectable level of 8 × 10
3 cells/ml of
Salmonella typhimurium in buffer was achieved in ca. 80 min.