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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

CV of (A) bare gold electrode, (B) MPA functionalization, and (C) antibody binding. The measurements were made in the presence of Fe(CN6)3–/4– as the redox probe with scan rate of 100 mV/s.
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biosensors-02-00417-f003: CV of (A) bare gold electrode, (B) MPA functionalization, and (C) antibody binding. The measurements were made in the presence of Fe(CN6)3–/4– as the redox probe with scan rate of 100 mV/s.

Mentions: For electrochemical measurements, the CV was recorded before and after the deposition of the MPA monolayer. In Figure 3, the Fe(II)/Fe(III) redox peaks have decreased after the functionalization of the MPA monolayer. This can be attributed to the decrease of the electron transfer rate that was created by the compactness of the formulated SAMs. After antibody binding, the redox peaks decrease even more due to the decrease of the electron transfer rate. This was due to an increase of the biolayer thickness that was developed on the gold surface.


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)

CV of (A) bare gold electrode, (B) MPA functionalization, and (C) antibody binding. The measurements were made in the presence of Fe(CN6)3–/4– as the redox probe with scan rate of 100 mV/s.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

biosensors-02-00417-f003: CV of (A) bare gold electrode, (B) MPA functionalization, and (C) antibody binding. The measurements were made in the presence of Fe(CN6)3–/4– as the redox probe with scan rate of 100 mV/s.
Mentions: For electrochemical measurements, the CV was recorded before and after the deposition of the MPA monolayer. In Figure 3, the Fe(II)/Fe(III) redox peaks have decreased after the functionalization of the MPA monolayer. This can be attributed to the decrease of the electron transfer rate that was created by the compactness of the formulated SAMs. After antibody binding, the redox peaks decrease even more due to the decrease of the electron transfer rate. This was due to an increase of the biolayer thickness that was developed on the gold surface.

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