Detection of pathogenic Bacteria by Electrochemical Impedance Spectroscopy: Influence of the immobilization strategies on the sensor performance
| Autor: | Nuria Pascual, M.-P. Marco, M. Barreiros dos Santos, C. Sporer, J. Samiter, Vasco Teixeira, Abdelhamid Errachid, Elena Martinez, Nuria Sanvicens |
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| Rok vydání: | 2009 |
| Předmět: |
Detection limit
Chromatography medicine.diagnostic_test biology Chemistry(all) Chemistry 010401 analytical chemistry Analytical chemistry NeutrAvidin 02 engineering and technology General Medicine 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Dielectric spectroscopy Immunoassay Biotinylation Monolayer medicine biology.protein Chemical Engineering(all) Nyquist plot 0210 nano-technology Biosensor |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| ISSN: | 1876-6196 |
| DOI: | 10.1016/j.proche.2009.07.322 |
| Popis: | Electrochemical impedance spectroscopy (EIS) is applied to detect pathogenic E. coli O157:H7 bacteria via a label free immunoassay-based detection method. Polyclonal anti-E.coli antibodies (PAb) are immobilized onto gold electrodes following two different strategies, via chemical bond formation between antibody amino groups and a carboxylic acid containing self-assembled molecular monolayer (SAM) and alternatively by linking a biotinylated anti-E. coli to Neutravidin on a mixed-SAM. Impedance spectra for sensors of both designs for increasing concentrations of E. coli are recorded in phosphate buffered saline (PBS). The Nyquist plots can be modeled with a Randle equivalent circuit, identifying the charge transfer resistance RCT as the relevant concentration dependent parameter. Sensors fabricated from both designs are able to detect very low concentration of E. coli with limits of detection as low as 10-100 cfu/ml. The influence of the different immobilization protocols on the sensor performance is evaluated in terms of sensitivity, dynamic range and resistance against nonspecific absorption. |
| Databáze: | OpenAIRE |
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