title: Field-effect sensors with charged macromolecules: characterisation by capacitance-voltage, constant-capacitance, impedance spectroscopy and atomic-force microscopy methods.
abstract: Field-effect-based capacitive electrolyte-insulator-semiconductor (EIS) sensors have been utilised for the deoxyribonucleic acid (DNA) immobilisation and hybridisation detection as well as for monitoring the layer-by-layer adsorption of polyelectrolytes (anionic poly(sodium 4-styrene sulfonate) (PSS) and cationic poly(allylamine hydrochloride) (PAH)). The EIS sensors with charged macromolecules have been systematically characterised by capacitance-voltage, constant-capacitance, impedance spectroscopy and atomic-force microscopy methods. The effect of the number and polarity of the polyelectrolyte layers on the shift of the capacitance-voltage curves has been investigated. Alternating potential shifts of about 30-90 mV have been observed after the adsorption of each polyanion and polycation layer, respectively. The DNA immobilisation and hybridisation signals were 35-55 and 24-33 mV, respectively. The possible mechanisms for the sensor responses are discussed.
authors.affiliation: Aachen University of Applied Sciences (Jülich Campus), Laboratory for Chemical Sensors and Biosensors, Ginsterweg 1, D-52428 Jülich, Germany. a.poghossian@fz-juelich.de
authors.forename: A
authors.initials: A
authors.lastname: Poghossian
authors.forename: M H
authors.initials: MH
authors.lastname: Abouzar
authors.forename: F
authors.initials: F
authors.lastname: Amberger
authors.forename: D
authors.initials: D
authors.lastname: Mayer
authors.forename: Y
authors.initials: Y
authors.lastname: Han
authors.forename: S
authors.initials: S
authors.lastname: Ingebrandt
authors.forename: A
authors.initials: A
authors.lastname: Offenhäusser
authors.forename: M J
authors.initials: MJ
authors.lastname: Schöning
mesh_terms: D004247:DNA / Q000737:chemistry*; D025802:Electric Capacitance; D017097:Electric Impedance; D018625:Microscopy, Atomic Force; D009693:Nucleic Acid Hybridization; D011073:Polyamines; D011108:Polymers; D013451:Sulfonic Acids
chemical_list: D011073:Polyamines; D011108:Polymers; D013451:Sulfonic Acids; C063994:polyallylamine; D004247:DNA; C077114:styrenesulfonic acid polymer