TY  - JOUR
A1  - Poghossian, Arshak
A1  - Karschuck, Tobias
A1  - Wagner, Patrick
A1  - Schöning, Michael Josef
T1  - Field-Effect Capacitors Decorated with Ligand-Stabilized Gold Nanoparticles: Modeling and Experiments
JF  - Biosensors
N2  - Nanoparticles are recognized as highly attractive tunable materials for designing field-effect biosensors with enhanced performance. In this work, we present a theoretical model for electrolyte-insulator-semiconductor capacitors (EISCAP) decorated with ligand-stabilized charged gold nanoparticles. The charged AuNPs are taken into account as additional, nanometer-sized local gates. The capacitance-voltage (C–V) curves and constant-capacitance (ConCap) signals of the AuNP-decorated EISCAPs have been simulated. The impact of the AuNP coverage on the shift of the C–V curves and the ConCap signals was also studied experimentally on Al–p-Si–SiO₂ EISCAPs decorated with positively charged aminooctanethiol-capped AuNPs. In addition, the surface of the EISCAPs, modified with AuNPs, was characterized by scanning electron microscopy for different immobilization times of the nanoparticles.
KW  - aminooctanethiol
KW  - nanoparticle coverage
KW  - capacitive model
KW  - gold nanoparticles
KW  - field-effect sensor
KW  - electrolyte-insulator-semiconductor capacitors
Y1  - 2022
U6  - http://dx.doi.org/10.3390/bios12050334
SN  - 2079-6374
N1  - This article belongs to the Special Issue "Biosensors in Nanotechnology"
VL  - 12
IS  - 5
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Karschuck, Tobias
A1  - Kaulen, Corinna
A1  - Poghossian, Arshak
A1  - Wagner, Patrick H.
A1  - Schöning, Michael Josef
T1  - Gold nanoparticle-modified capacitive field-effect sensors: Studying the surface density of nanoparticles and coupling of charged polyelectrolyte macromolecules
JF  - Electrochemical Science Advances
N2  - The coupling of ligand-stabilized gold nanoparticles with field-effect devices offers new possibilities for label-free biosensing. In this work, we study the immobilization of aminooctanethiol-stabilized gold nanoparticles (AuAOTs) on the silicon dioxide surface of a capacitive field-effect sensor. The terminal amino group of the AuAOT is well suited for the functionalization with biomolecules. The attachment of the positively-charged AuAOTs on a capacitive field-effect sensor was detected by direct electrical readout using capacitance-voltage and constant capacitance measurements. With a higher particle density on the sensor surface, the measured signal change was correspondingly more pronounced. The results demonstrate the ability of capacitive field-effect sensors for the non-destructive quantitative validation of nanoparticle immobilization. In addition, the electrostatic binding of the polyanion polystyrene sulfonate to the AuAOT-modified sensor surface was studied as a model system for the label-free detection of charged macromolecules. Most likely, this approach can be transferred to the label-free detection of other charged molecules such as enzymes or antibodies.
KW  - polystyrene sulfonate
KW  - gold nanoparticles
KW  - field-effect sensor
KW  - detection of charged macromolecules
KW  - capacitive EIS sensor
Y1  - 2021
U6  - http://dx.doi.org/10.1002/elsa.202100179
SN  - 0938-5193
VL  - 2
IS  - 5
PB  - Wiley-VCH
CY  - Weinheim
ER  -