Detection of Salmonella in food using electrochemical and surface plasmon resonance immunosensors
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| Year of publication | 2017 |
| Type | Conference abstract |
| MU Faculty or unit | |
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| Description | Foodborne pathogens represent a serious risk to public health, resulting in a growing demand for technologies capable of rapid and sensitive detection of bacteria. Electrochemical impedance spectroscopy (EIS) and surface plasmon resonance (SPR) immunosensors were developed for the analysis of Salmonella in food samples. Both approaches were focused on simplicity and robustness of the assay while providing a short analysis time and high sensitivity. The label-free EIS biosensor was based on anti-Salmonella antibody immobilized to a screenprinted electrode via cysteamine self-assembled monolayer activated by glutaraldehyde. The assay based on direct incubation with food sample followed by the measurement of impedance between two gold electrodes provided results within 20 min. Limit of detection (LOD) of 10^3 CFU/mL and wide linear range up to 10^8 CFU/mL were achieved. Signal enhancement by enzymatic precipitation was developed for the SPR immunosensing. A sandwich immunocomplex consisting of a capture antibody, Salmonella and a detection antibody conjugated with horseradish peroxidase (HRP) was formed on the SPR chip. The biocatalyzed conversion of 4-chloro-1-naphthol to insoluble benzo-4-chlorocyclohexadienone was carried out resulting in a significant increase of sensitivity compared to a label-free approach. The optimized method provided LOD of 100 CFU/mL with linear range up to 10^6 CFU/mL (Figure 1). The whole analysis including the injection of bacteria and the enhancement step did not exceed 60 min. The developed immunosensors represent simple and robust approach for routine monitoring of food contamination. |
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