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Capacitive electrolyte-insulator-semiconductor structures functionalised with a polyelectrolyte/enzyme multilayer: New strategy for enhanced field-effect biosensing

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...

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Bibliographic Details
Published in:Physica status solidi. A, Applications and materials science Applications and materials science, 2010-04, Vol.207 (4), p.884-890
Main Authors: Abouzar, Maryam H., Poghossian, Arshak, Siqueira Jr, José R., Oliveira Jr, Osvaldo N., Moritz, Werner, Schöning, Michael J.
Format: Article
Language:English
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Summary: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–SiO2 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%).
ISSN:1862-6300
1862-6319
DOI:10.1002/pssa.200983317