Limits...
An Electrochemical Immunosensor for Detection of Staphylococcus aureus Bacteria Based on Immobilization of Antibodies on Self-Assembled Monolayers-Functionalized Gold Electrode.

Braiek M, Rokbani KB, Chrouda A, Mrabet B, Bakhrouf A, Maaref A, Jaffrezic-Renault N - Biosensors (Basel) (2012)

Bottom Line: The EIS technique was used for affinity assays: antibody-cell binding.The limit of detection (LOD) was observed at 10 CFU/mL, and the reproducibility was calculated to 8%.Finally, a good selectivity versus E. coli and S. epidermidis was obtained for our developed immunosensor demonstrating its specificity towards only S. aureus.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire de Physique et Chimie des Interfaces, Faculté des Sciences de Monastir, Tunisie, Avenue de l'Environnement, 5019 Monastir, Tunisia. mohamed_braiek@yahoo.fr.

ABSTRACT
The detection of pathogenic bacteria remains a challenge for the struggle against biological weapons, nosocomial diseases, and for food safety. In this research, our aim was to develop an easy-to-use electrochemical immunosensor for the detection of pathogenic Staphylococcus aureus ATCC25923. The biosensor was elaborated by the immobilization of anti-S. aureus antibodies using a self-assembled monolayer (SAMs) of 3-Mercaptopropionic acid (MPA). These molecular assemblies were spontaneously formed by the immersion of the substrate in an organic solvent containing the SAMs that can covalently bond to the gold surface. The functionalization of the immunosensor was characterized using two electrochemical techniques: cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Here, the analysis was performed in phosphate buffer with ferro/ferricyanide as the redox probe. The EIS technique was used for affinity assays: antibody-cell binding. A linear relationship between the increment in the electron transfer resistance (RCT) and the logarithmic value of S. aureus concentration was observed between 10 and 106 CFU/mL. The limit of detection (LOD) was observed at 10 CFU/mL, and the reproducibility was calculated to 8%. Finally, a good selectivity versus E. coli and S. epidermidis was obtained for our developed immunosensor demonstrating its specificity towards only S. aureus.

No MeSH data available.


Related in: MedlinePlus

Electrochemical detection of (A) Bode plot, and (B) Nyquist plot of impedance spectra obtained from the increasing concentration of S. aureus (ATCC25923) from 10 to 107 CFU/mL in PBS and Fe(CN6)3–/4–.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4263564&req=5

biosensors-02-00417-f005: Electrochemical detection of (A) Bode plot, and (B) Nyquist plot of impedance spectra obtained from the increasing concentration of S. aureus (ATCC25923) from 10 to 107 CFU/mL in PBS and Fe(CN6)3–/4–.

Mentions: The impedance measurement for the direct detection of bacterial cells is generally known to have improved significance by analysis with a Bode plot. This technique is suitable for studying the direct relationship of impedance with the frequency [16]. Here, the binding ability of bacteria and the bioreceptor was then verified through the EIS technique. In Figure 5, we show (A) the Bode plot, and (B) the Nyquist diagram that were obtained after incubation in an increasing concentration of the target bacteria. Here, the charge transfer resistance (RCT) increases gradually as the bacteria concentration increases after consecutive incubations. This was made from 10 CFU/mL to 107 CFU/mL.


An Electrochemical Immunosensor for Detection of Staphylococcus aureus Bacteria Based on Immobilization of Antibodies on Self-Assembled Monolayers-Functionalized Gold Electrode.

Braiek M, Rokbani KB, Chrouda A, Mrabet B, Bakhrouf A, Maaref A, Jaffrezic-Renault N - Biosensors (Basel) (2012)

Electrochemical detection of (A) Bode plot, and (B) Nyquist plot of impedance spectra obtained from the increasing concentration of S. aureus (ATCC25923) from 10 to 107 CFU/mL in PBS and Fe(CN6)3–/4–.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263564&req=5

biosensors-02-00417-f005: Electrochemical detection of (A) Bode plot, and (B) Nyquist plot of impedance spectra obtained from the increasing concentration of S. aureus (ATCC25923) from 10 to 107 CFU/mL in PBS and Fe(CN6)3–/4–.
Mentions: The impedance measurement for the direct detection of bacterial cells is generally known to have improved significance by analysis with a Bode plot. This technique is suitable for studying the direct relationship of impedance with the frequency [16]. Here, the binding ability of bacteria and the bioreceptor was then verified through the EIS technique. In Figure 5, we show (A) the Bode plot, and (B) the Nyquist diagram that were obtained after incubation in an increasing concentration of the target bacteria. Here, the charge transfer resistance (RCT) increases gradually as the bacteria concentration increases after consecutive incubations. This was made from 10 CFU/mL to 107 CFU/mL.

Bottom Line: The EIS technique was used for affinity assays: antibody-cell binding.The limit of detection (LOD) was observed at 10 CFU/mL, and the reproducibility was calculated to 8%.Finally, a good selectivity versus E. coli and S. epidermidis was obtained for our developed immunosensor demonstrating its specificity towards only S. aureus.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire de Physique et Chimie des Interfaces, Faculté des Sciences de Monastir, Tunisie, Avenue de l'Environnement, 5019 Monastir, Tunisia. mohamed_braiek@yahoo.fr.

ABSTRACT
The detection of pathogenic bacteria remains a challenge for the struggle against biological weapons, nosocomial diseases, and for food safety. In this research, our aim was to develop an easy-to-use electrochemical immunosensor for the detection of pathogenic Staphylococcus aureus ATCC25923. The biosensor was elaborated by the immobilization of anti-S. aureus antibodies using a self-assembled monolayer (SAMs) of 3-Mercaptopropionic acid (MPA). These molecular assemblies were spontaneously formed by the immersion of the substrate in an organic solvent containing the SAMs that can covalently bond to the gold surface. The functionalization of the immunosensor was characterized using two electrochemical techniques: cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Here, the analysis was performed in phosphate buffer with ferro/ferricyanide as the redox probe. The EIS technique was used for affinity assays: antibody-cell binding. A linear relationship between the increment in the electron transfer resistance (RCT) and the logarithmic value of S. aureus concentration was observed between 10 and 106 CFU/mL. The limit of detection (LOD) was observed at 10 CFU/mL, and the reproducibility was calculated to 8%. Finally, a good selectivity versus E. coli and S. epidermidis was obtained for our developed immunosensor demonstrating its specificity towards only S. aureus.

No MeSH data available.


Related in: MedlinePlus