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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

Positive-to-negative response ratio of the developed immunosensor for (A) E. coli, and (B) S. epidermidis bacteria.
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biosensors-02-00417-f008: Positive-to-negative response ratio of the developed immunosensor for (A) E. coli, and (B) S. epidermidis bacteria.

Mentions: E. coli and Staphylococcus epidermidis (S. epidermidis) were detected in order to determine the specificity of our impedimetric immunosensor. These two bacteria are the most abundant strains found in real samples. The same protocol was followed for the surface functionalization using anti-S. aureus. Here, the antibody was immobilized and the electrodes were exposed to the suspensions of E. coli and S. epidermidis. In a similar manner to the detection of S. aureus, the concentrations of the two bacteria were increased in order to observe if there was a significant effect on the immunosensor by EIS. In Figure 8, the positive-to-negative response ratios of the immunosensor for non-specific targets (E. coli and S. epidermidis) are given. The results show a higher selectivity for E. coli compared to S. epidermidis.


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)

Positive-to-negative response ratio of the developed immunosensor for (A) E. coli, and (B) S. epidermidis bacteria.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

biosensors-02-00417-f008: Positive-to-negative response ratio of the developed immunosensor for (A) E. coli, and (B) S. epidermidis bacteria.
Mentions: E. coli and Staphylococcus epidermidis (S. epidermidis) were detected in order to determine the specificity of our impedimetric immunosensor. These two bacteria are the most abundant strains found in real samples. The same protocol was followed for the surface functionalization using anti-S. aureus. Here, the antibody was immobilized and the electrodes were exposed to the suspensions of E. coli and S. epidermidis. In a similar manner to the detection of S. aureus, the concentrations of the two bacteria were increased in order to observe if there was a significant effect on the immunosensor by EIS. In Figure 8, the positive-to-negative response ratios of the immunosensor for non-specific targets (E. coli and S. epidermidis) are given. The results show a higher selectivity for E. coli compared to S. epidermidis.

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