Publication details
Electrochemical biosensors for detection of pathogenic bacteria
| Authors | |
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| Year of publication | 2018 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | Rapid detection and identification of low levels of pathogenic bacteria remains challenging for point-of-care clinical diagnosis, food testing and environmental screening. Conventional methods for detection of bacteria such as culturing methods, ELISA or PCR provide high sensitivity, however the analysis is rather slow, which is a major drawback in situations when spreading of the pathogen has to be prevented. Besides the traditional methods, immunosensors (biosensors based on antibodies) are extensively developed as an alternative for rapid and sensitive detection, robustness, ease of operation and potential in-field application. A label-free biosensor based on electrochemical impedance spectroscopy (EIS) was developed for the detection of Salmonella Typhimurium in milk. Specific antibody was immobilized on a screen-printed electrode, the electrode was incubated with sample and binding of bacteria was measured as a change of impedance. Different procedures for sample treatment (combinations of heat treatment and sonication) were tested and their impact on the assay performance was compared. Atomic force microscopy (AFM) was used to study the effect of the treatment on the cell shape and to confirm the specific binding of Salmonella to the sensing surface. The immunosensor allowed detection of 1×10^3 CFU·mL-1 in 20 min with negligible interference from other bacteria. A wide linear response was obtained in the range between 10^3 and 10^8 CFU·mL-1. The successful detection of Salmonella in spiked milk demonstrates the suitability of sensor for the analysis of real samples. The method did not require any pre-enrichment of bacteria, making the assay fast and simple, however the sensitivity can be further enhanced by employment of the enzymatic precipitation approach. Other bacteria can be also detected when appropriate specific antibodies are used. When combined with a portable measuring system, the developed immunosensor would be suitable for routine in-field testing. |
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