Influence of antibody immobilization strategies on the analytical performance of a magneto-elastic immunosensor for Staphylococcus aureus detection
| Autor: | M. Beltrami, C. Menti, Sandro Tomaz Martins, João Antonio Pêgas Henriques, Marcia Dalla Pozza, Frank P. Missell, Abel D. Santos, Mariana Roesch-Ely |
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| Rok vydání: | 2016 |
| Předmět: |
Analyte
Staphylococcus aureus Analytical chemistry Bioengineering 02 engineering and technology Magneto elastic Biosensing Techniques medicine.disease_cause Microscopy Atomic Force 01 natural sciences Antibodies Biomaterials Microscopy medicine Chromatography biology Chemistry 010401 analytical chemistry IIf 021001 nanoscience & nanotechnology biology.organism_classification 0104 chemical sciences Mechanics of Materials Covalent bond biology.protein Antibody 0210 nano-technology Bacteria |
| Zdroj: | Materials scienceengineering. C, Materials for biological applications. 76 |
| ISSN: | 1873-0191 |
| Popis: | Magneto-elastic (ME) sensors have a great advantage in microbiology due to their ability to be queried wirelessly. Staphylococcus aureus is one of the most common bacteria widespread in the environment and a major human pathogen related to numerous illnesses. Immunosensors are affinity-based assays where the analyte is highly selective. The immobilization of antibodies (Ab) is an important step in the development of such devices. This study compared the effects of two antibody immobilization strategies on the analytical performance of a magneto-elastic immunosensor: (1) random antibody covalent immobilization (CysAb) and (2) specific-oriented antibody covalent immobilization (PrGAb). Immunosensors were exposed to solutions containing S. aureus at different concentrations (104 to 108CFU/ml) and sensor resonant frequencies were measured. In order to confirm that the frequency shifts were mainly caused by the binding of S. aureus to the sensor's surface, scanning electron microscope (SEM) and indirect immunofluorescence (IIF) images were taken after bacteria exposure at 108CFU/ml. Sensor surfaces were further monitored by non-contact topographic atomic force microscopy (AFM) images. In the covalent-oriented strategy, PrG was first bound covalently to the surface, which in turn, then binds the anti-S. aureus antibody in an oriented manner. Topographic AFM images showed different surface patterns between the two antibody immobilization strategies. Specific-oriented antibody covalent immobilization (PrGAb) strategy gave the highest anti-S. aureus antibody immobilization density. Therefore, the covalent-oriented strategy presented the best performance for S. aureus capture, detecting 104CFU/ml. |
| Databáze: | OpenAIRE |
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