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  - Poghossian, Arshak
A1  - Ser, Joey
A1  - Tsokolakyan, Astghik
A1  - Achtsnicht, Stefan
A1  - Wagner, Patrick
A1  - Schöning, Michael Josef
T1  - Capacitive model of enzyme-modified field-effect biosensors: Impact of enzyme coverage
JF  - Sensors and Actuators B: Chemical
N2  - Electrolyte-insulator-semiconductor capacitors (EISCAP) belong to field-effect sensors having an attractive transducer architecture for constructing various biochemical sensors. In this study, a capacitive model of enzyme-modified EISCAPs has been developed and the impact of the surface coverage of immobilized enzymes on its capacitance-voltage and constant-capacitance characteristics was studied theoretically and experimentally. The used multicell arrangement enables a multiplexed electrochemical characterization of up to sixteen EISCAPs. Different enzyme coverages have been achieved by means of parallel electrical connection of bare and enzyme-covered single EISCAPs in diverse combinations. As predicted by the model, with increasing the enzyme coverage, both the shift of capacitance-voltage curves and the amplitude of the constant-capacitance signal increase, resulting in an enhancement of analyte sensitivity of the EISCAP biosensor. In addition, the capability of the multicell arrangement with multi-enzyme covered EISCAPs for sequentially detecting multianalytes (penicillin and urea) utilizing the enzymes penicillinase and urease has been experimentally demonstrated and discussed.
KW  - Field-effect biosensor
KW  - Capacitive model
KW  - Enzyme coverage
KW  - Multianalyte detection
KW  - Penicillin
Y1  - 2024
U6  - http://dx.doi.org/10.1016/j.snb.2024.135530
SN  - 0925-4005 (Print)
SN  - 1873-3077 (Online)
N1  - Corresponding Author: Michael J. Schöning
VL  - 408
PB  - Elsevier
CY  - Amsterdam
ER  -