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Capacitive electrolyte–insulator–semiconductor structures functionalised with a polyelectrolyte/enzyme multilayer: New strategy for enhanced field‐effect biosensing
Author(s) -
Abouzar Maryam H.,
Poghossian Arshak.,
Siqueira José R.,
Oliveira Osvaldo N.,
Moritz Werner,
Schöning Michael J.
Publication year - 2010
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200983317
Subject(s) - biosensor , allylamine , polyelectrolyte , dendrimer , electrolyte , materials science , capacitive sensing , immobilized enzyme , chemistry , chemical engineering , polymer , nanotechnology , polymer chemistry , electrode , enzyme , organic chemistry , composite material , computer science , operating system , engineering
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%).