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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

A comparative study of the response of the modified electrode (relative variation of RCT) in the presence and absence of antibodies.
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getmorefigures.php?uid=PMC4263564&req=5

biosensors-02-00417-f007: A comparative study of the response of the modified electrode (relative variation of RCT) in the presence and absence of antibodies.

Mentions: A comparative study was made to ensure that the response of the immunosensor was a direct cause of the immobilized antibody and not due to adsorption of bacteria on the surface modified SAMs. Here, different electrodes were functionalized in the same conditions as our immunosensor, but without the antibody incubation step. The results show that there is not a significant variation of the response for the modified electrode (relative variation of RCT) after incubation of the electrode in varying staphylococcus concentrations (Figure 7). The fixation of the antibody is a logical approach for the high detection of these pathogenic bacteria.


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)

A comparative study of the response of the modified electrode (relative variation of RCT) in the presence and absence of antibodies.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

biosensors-02-00417-f007: A comparative study of the response of the modified electrode (relative variation of RCT) in the presence and absence of antibodies.
Mentions: A comparative study was made to ensure that the response of the immunosensor was a direct cause of the immobilized antibody and not due to adsorption of bacteria on the surface modified SAMs. Here, different electrodes were functionalized in the same conditions as our immunosensor, but without the antibody incubation step. The results show that there is not a significant variation of the response for the modified electrode (relative variation of RCT) after incubation of the electrode in varying staphylococcus concentrations (Figure 7). The fixation of the antibody is a logical approach for the high detection of these pathogenic bacteria.

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