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Issue 3, 2015
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Gating capacitive field-effect sensors by the charge of nanoparticle/molecule hybrids

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Abstract

The semiconductor field-effect platform is a powerful tool for chemical and biological sensing with direct electrical readout. In this work, the field-effect capacitive electrolyte–insulator–semiconductor (EIS) structure – the simplest field-effect (bio-)chemical sensor – modified with citrate-capped gold nanoparticles (AuNPs) has been applied for a label-free electrostatic detection of charged molecules by their intrinsic molecular charge. The EIS sensor detects the charge changes in AuNP/molecule inorganic/organic hybrids induced by the molecular adsorption or binding events. The feasibility of the proposed detection scheme has been exemplarily demonstrated by realizing capacitive EIS sensors consisting of an Al–p-Si–SiO2–silane–AuNP structure for the label-free detection of positively charged cytochrome c and poly-D-lysine molecules as well as for monitoring the layer-by-layer formation of polyelectrolyte multilayers of poly(allylamine hydrochloride)/poly(sodium 4-styrene sulfonate), representing typical model examples of detecting small proteins and macromolecules and the consecutive adsorption of positively/negatively charged polyelectrolytes, respectively. For comparison, EIS sensors without AuNPs have been investigated, too. The adsorption of molecules on the surface of AuNPs has been verified via the X-ray photoelectron spectroscopy method. In addition, a theoretical model of the functioning of the capacitive field-effect EIS sensor functionalized with AuNP/charged-molecule hybrids has been discussed.

Graphical abstract: Gating capacitive field-effect sensors by the charge of nanoparticle/molecule hybrids

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Publication details

The article was received on 10 Oct 2014, accepted on 19 Nov 2014 and first published on 21 Nov 2014


Article type: Paper
DOI: 10.1039/C4NR05987E
Nanoscale, 2015,7, 1023-1031

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    Gating capacitive field-effect sensors by the charge of nanoparticle/molecule hybrids

    A. Poghossian, M. Bäcker, D. Mayer and M. J. Schöning, Nanoscale, 2015, 7, 1023
    DOI: 10.1039/C4NR05987E

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