158 articles – 194 references  [version française]
Detailed view Article in peer-reviewed journal
Analytical Chemistry 79, 13 (2007) 4879-4886
Label-free detection of bacteria by electrochemical impedance spectroscopy: Comparison to surface plasmon resonance
Rita Maalouf1, Chantal Fournier-Wirth, Joliette Coste, Hanna Chebib1, Youssef Saikali2, Olivier Vittori2, Abdelhamid Errachid3, Jean-Pierre Cloarec4, Claude Martelet5, Nicole Jaffrezic-Renault2

The low but known risk of bacterial contamination has emerged as the greatest residual threat of transfusion-transmitted diseases. Label-free detection of a bacterial model, Escherichia coli, is performed using nonfaradic electrochemical impedance spectroscopy (EIS). Biotinylated polyclonal anti-E. coli is linked to a mixed self-assembled monolayer (SAM) on a gold electrode through a strong biotin-neutravidin interaction. The binding of one antibody molecule for 3.6 neutravidin molecules is determined using the surface plasmon resonance (SPR). The detection limit of E. coli found by SPR is 10(7) cfu/mL. After modeling the impedance Nyquist plot of E. coli/anti-E. coli/mixed SAM/gold electrode for increasing concentrations of E. coli (whole bacteria or lysed bacteria), the main parameter that is modified is the polarization resistance R-P. A sigmoid variation of R-P is observed when the log concentration of bacteria (whole or lysed) increases. A concentration of 10 cfu/mL whole bacteria is detected by EIS measurements while 10(3) cfu/mL is detected for lysed E. coli.
1:  Laboratory of Chemistry
2:  SA - Sciences Analytiques
3:  Lab NanoBioEngn
4:  INL - Institut des nanotechnologies de Lyon - Site d'Ecully
5:  Ampère
ESCHERICHIA-COLI O157-H7 – SELF-ASSEMBLED MONOLAYER – RAPID DETECTION – PATHOGENIC BACTERIA – ARRAY BIOSENSOR – IMMUNOSENSOR – SYSTEM – SENSOR – IDENTIFICATION – CAPACITANCE