Citation:
Faridah Salam, Ibtisam E. Tothill, Detection of Salmonella typhimurium using an electrochemical immunosensor, Biosensors and Bioelectronics, Volume 24, Issue 8, 15 April 2009, Pages 2630-2636
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)/H2O2
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–H2O2–IgG–HRP
system. S. typhimurium detection of 5 × 103 cells ml−1 and 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