| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 867338 | Biosensors and Bioelectronics | 2012 | 8 Pages |
Rapid and sensitive detections of microorganisms are very important for biodefence, food safety, medical diagnosis and pharmaceutics. The present study aims to find out the most proper bioactive surface preparation method to develop rapid, sensitive and selective bacteria biosensor, based on surface plasmon resonance (SPR) spectroscopy. Escherichia coli (E. coli) was used as a model bacterium and four sensing strategies in SPR were tested. Three of these strategies are antibody immobilization methods that are non-specific adsorption, specific adsorption via the avidin–biotin interaction, and immobilization of antibodies via self-assembled monolayer formation. The fourth strategy is a novel method for bacteria enumeration based on the combination of the SPR spectroscopy and immunomagnetic separation with using gold-coated magnetic nanoparticles. According to results, the most efficient SPR method is the one based on gold-coated magnetic nanoparticles. This method allows to specifically separate E. coli from the environment and to quantify rapidly without any labeling procedure. The developed method has a linear range between 30 and 3.0×104 cfu/ml, and a detection limit of 3 cfu/ml. The selectivity of the method was examined with Enterobacter aerogenes and Enterobacter dissolvens, which did not produce any significant response. The usefulness of the method to detect E. coli in real water samples was also investigated, and the results were compared with the results from plate-counting method. There was no significant difference between the methods (p>0.05).
► Four sensing strategies in SPR biosensor were tested and compared for E. coli enumeration. ► The most sensitive and rapid method was the one based on gold-coated magnetic nanoparticles. ► With this method, the linear range was obtained between 30 and 3.0×104 cfu/ml. ► The limit of detection was found to be as 3 cfu/ml. ► E. coli determination was also realized for the real water samples with the developed method.
