Development of a capacitive immunosensor: a comparison of monoclonal and polyclonal capture antibodies as the primary layer
✍ Scribed by Helen C. Berney; John Alderman; William A. Lane; John K. Collins
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 57 KB
- Volume
- 11
- Category
- Article
- ISSN
- 0952-3499
No coin nor oath required. For personal study only.
✦ Synopsis
There is widespread interest in capacitance immunosensor systems which directly detect antigen binding to immobilized antibody. Our system comprises an active biolayer of antibodies bound to a silicon-silicon dioxide-silicon nitride (Si-SiO 2 -Si 3 N 4 ) surface. As with other groups, our system initially gave poorly reproducible responses on addition of antigen. We mechanically degraded the Si-SiO 2 -Si 3 N 4 surface, and the responses on addition of transferrin were monitored. The mechanical degradation allowed the affinity reaction to be 'seen' capacitively. Once the system was established, a comparison of capture antibodies was performed to establish the most effective biolayer. Three affinity reactions were examined: (a) 1D 2 A 4 , monoclonal antibody (mAb) to human transferrin, as the capture layer; (b) polyclonal goat anti-human transferrin antibody (PcAb) as the capture layer; and (c) 1D 2 A 4 with transferrin (Tf) prebound as the capture layer. There was no response to addition of transferrin where 1D 2 A 4 was the capture layer. Addition of transferrin when the polyclonal antibody was used as the primary layer resulted in a drop in measured capacitance. Addition of goat anti-human transferrin antibody to a device with 1D 2 A 4 plus transferrin as the capture layer also resulted in a measured capacitance decrease. There is a difference in dielectric/blocking effectiveness between the monoclonal and polyclonal antibodies.