Capacitive electrolyte–insulator–semiconductor structures functionalised with a polyelectrolyte/enzyme multilayer: New strategy for enhanced field-effect biosensing
✍ Scribed by Maryam H. Abouzar; Arshak. Poghossian; José R. Siqueira Jr.; Osvaldo N. Oliveira Jr.; Werner Moritz; Michael J. Schöning
- Book ID
- 105365771
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- English
- Weight
- 571 KB
- Volume
- 207
- Category
- Article
- ISSN
- 0031-8965
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✦ Synopsis
Abstract
A novel strategy for enhanced field‐effect biosensing using capacitive electrolyte–insulator–semiconductor (EIS) structures functionalised with pH‐responsive weak polyelectrolyte/enzyme or dendrimer/enzyme multilayers is presented. The feasibility of the proposed approach is exemplarily demonstrated by realising a penicillin biosensor based on a capacitive p‐Si–SiO~2~ EIS structure functionalised with a poly(allylamine hydrochloride) (PAH)/penicillinase and a poly(amidoamine) dendrimer/penicillinase multilayer. The developed sensors response to changes in both the local pH value near the gate surface and the charge of macromolecules induced via enzymatic reaction, resulting in a higher sensitivity. For comparison, an EIS penicillin biosensor with adsorptively immobilised penicillinase has been also studied. The highest penicillin sensitivity of 100 mV/dec has been observed for the EIS sensor functionalised with the PAH/penicillinase multilayer. The lower and upper detection limit was around 20 µM and 10 mM, respectively. In addition, an incorporation of enzymes in a multilayer prepared by layer‐by‐layer technique provides a larger amount of immobilised enzymes per sensor area, reduces enzyme leaching effects and thus, enhances the biosensor lifetime (the loss of penicillin sensitivity after 2 months was 10–12%).