TY  - JOUR
A1  - Wu, Chunsheng
A1  - Poghossian, Arshak
A1  - Bronder, Thomas
A1  - Schöning, Michael Josef
T1  - Sensing of double-stranded DNA molecules by their intrinsic molecular charge using the light-addressable potentiometric sensor
JF  - Sensors and Actuators B: Chemical
N2  - A multi-spot light-addressable potentiometric sensor (LAPS), which belongs to the family of semiconductor field-effect devices, was applied for label-free detection of double-stranded deoxyribonucleic acid (dsDNA) molecules by their intrinsic molecular charge. To reduce the distance between the DNA charge and sensor surface and thus, to enhance the electrostatic coupling between the dsDNA molecules and the LAPS, the negatively charged dsDNA molecules were electrostatically adsorbed onto the gate surface of the LAPS covered with a positively charged weak polyelectrolyte layer of PAH (poly(allylamine hydrochloride)). The surface potential changes in each spot of the LAPS, induced by the layer-by-layer adsorption of a PAH/dsDNA bilayer, were recorded by means of photocurrent-voltage and constant-photocurrent measurements. In addition, the surface morphology of the gate surface before and after consecutive electrostatic adsorption of PAH and dsDNA layers was studied by atomic force microscopy measurements. Moreover, fluorescence microscopy was used to verify the successful adsorption of dsDNA molecules onto the PAH-modified LAPS surface. A high sensor signal of 25 mV was registered after adsorption of 10 nM dsDNA molecules. The lower detection limit is down to 0.1 nM dsDNA. The obtained results demonstrate that the PAH-modified LAPS device provides a convenient and rapid platform for the direct label-free electrical detection of in-solution hybridized dsDNA molecules.
KW  - Layer-by-layer adsorption
KW  - Poly(allylamine hydrochloride)
KW  - Label-free detection
KW  - DNA biosensor
KW  - LAPS
KW  - Field effect
Y1  - 2016
U6  - http://dx.doi.org/10.1016/j.snb.2016.02.004
SN  - 0925-4005
IS  - 229
SP  - 506
EP  - 512
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Jablonski, Melanie
A1  - Poghossian, Arshak
A1  - Keusgen, Michael
A1  - Wege, Christina
A1  - Schöning, Michael Josef
T1  - Detection of plant virus particles with a capacitive field-effect sensor
JF  - Analytical and Bioanalytical Chemistry
N2  - Plant viruses are major contributors to crop losses and induce high economic costs worldwide. For reliable, on-site and early detection of plant viral diseases, portable biosensors are of great interest. In this study, a field-effect SiO2-gate electrolyte-insulator-semiconductor (EIS) sensor was utilized for the label-free electrostatic detection of tobacco mosaic virus (TMV) particles as a model plant pathogen. The capacitive EIS sensor has been characterized regarding its TMV sensitivity by means of constant-capacitance method. The EIS sensor was able to detect biotinylated TMV particles from a solution with a TMV concentration as low as 0.025 nM. A good correlation between the registered EIS sensor signal and the density of adsorbed TMV particles assessed from scanning electron microscopy images of the SiO2-gate chip surface was observed. Additionally, the isoelectric point of the biotinylated TMV particles was determined via zeta potential measurements and the influence of ionic strength of the measurement solution on the TMV-modified EIS sensor signal has been studied.
KW  - Plant virus
KW  - Capacitive field-effect sensor
KW  - Tobacco mosaic virus (TMV)
KW  - Label-free detection
KW  - Zeta potential
Y1  - 2021
U6  - http://dx.doi.org/10.1007/s00216-021-03448-8
SN  - 1618-2650
N1  - Corresponding authors: Arshak Poghossian & Michael J. Schöning
VL  - 413
SP  - 5669
EP  - 5678
PB  - Springer Nature
CY  - Cham
ER  - 
TY  - JOUR
A1  - Karschuck, Tobias
A1  - Schmidt, Stefan
A1  - Achtsnicht, Stefan
A1  - Poghossian, Arshak
A1  - Wagner, Patrick
A1  - Schöning, Michael Josef
T1  - Multiplexing system for automated characterization of a capacitive field-effect sensor array
JF  - Physica Status Solidi A
N2  - In comparison to single-analyte devices, multiplexed systems for a multianalyte detection offer a reduced assay time and sample volume, low cost, and high throughput. Herein, a multiplexing platform for an automated quasi-simultaneous characterization of multiple (up to 16) capacitive field-effect sensors by the capacitive–voltage (C–V) and the constant-capacitance (ConCap) mode is presented. The sensors are mounted in a newly designed multicell arrangement with one common reference electrode and are electrically connected to the impedance analyzer via the base station. A Python script for the automated characterization of the sensors executes the user-defined measurement protocol. The developed multiplexing system is tested for pH measurements and the label-free detection of ligand-stabilized, charged gold nanoparticles.
KW  - Capacitive field-effect sensor
KW  - Gold nanoparticles
KW  - Label-free detection
KW  - Multicell
KW  - Multiplexing
Y1  - 2023
U6  - http://dx.doi.org/10.1002/pssa.202300265
SN  - 1862-6300 (Print)
SN  - 1862-6319 (Online)
N1  - Corresponding author: Michael Josef Schöning
VL  - 220
IS  - 22
PB  - Wiley-VCH
CY  - Weinheim
ER  -